update from main archive 961206

Sat Dec  7 03:24:36 1996  Ulrich Drepper  <drepper@cygnus.com>

	* configure.in: Discard error message from test in test for
	bash-2.0.

	* io/getpw.c: Don't apply getcwd on user supplied buffer.
	Instead always use temporary buffer and only copy the result.
	Patch by HJ Lu.
	* stdlib/canonicalize.c: Likewise.

	* libio/fileops.c: Change comments according to libg++2.8b5.
	* libio/iosetvbuf.c: Follow change in libg++-2.8b5 to clear
	unbuffered flag.
	Reported by HJ Lu.

	* manual/nss.texi: Correct prototypes.

	* misc/syslog.c: Make reentrant.  Catch SIGPIPE signal to prevent
	crash if syslog daemon is restarted.

	* stdlib/rand_r.c: New file.  Implementation of POSIX.2 function
	rand_r.
	* stdlib/Makefile (routines): Add rand_r.

	* sysdeps/stub/libc-lock.h: Define __libc_lock_trylock and
	__libc_mutex_lock.

	* configure.in: Add --disable-sanity-check option.
	* sysdeps/unix/sysv/linux/configure.in: If linuxthreads or
	des-crypt are not available and --disbale-sanity-check is not
	given abort with a message.

Thu Dec  5 19:19:53 1996  Richard Henderson  <rth@tamu.edu>

	* posix/glob.c: Tests against STDC_HEADERS should also test
	__GNU_LIBRARY__.

Thu Dec  5 16:20:55 1996  Ulrich Drepper  <drepper@cygnus.com>

	* misc/err.c (vwarn): Set errno again before using %m format.

Thu Dec  5 10:14:05 1996  Andreas Jaeger  <aj@arthur.pfalz.de>

	* grp/grp.h: Add declaration of __getgrent_r.

	* io/fts.c (fts_build): Remove "register" from variables dirbuf
	and dp since their address is needed.

	* sysdeps/posix/getcwd.c (__getcwd): Remove "register" from
	variable d since d's address is needed.

	* misc/tst-dirname.c (main): Provide prototype.
	* misc/ioctltst.c (main): Dito.

	* Makefile: Add gnu/lib-names.h to install-others before including
	Makerules.

Wed Dec  4 16:00:09 1996  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/unix/sysv/linux/sys/socketvar.h: New file.  Simply use
	<sys/socket.h>.
	* sysdeps/unix/sysv/linux/Dist: Add sys/socketvar.h.
	* sysdeps/unix/sysv/linux/Makefile [$(subdir)=inet)]: Add
	sys/socketvar.h to sysdep_headers.

	since the value might be outside the range of the `long int'.

25 files changed, 382 insertions, 168 deletions

diff --git a/ChangeLog b/ChangeLog
index 6ffef25dd5..573b618221 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,68 @@
+Sat Dec  7 03:24:36 1996  Ulrich Drepper  <drepper@cygnus.com>
+
+	* configure.in: Discard error message from test in test for
+	bash-2.0.
+
+	* io/getpw.c: Don't apply getcwd on user supplied buffer.
+	Instead always use temporary buffer and only copy the result.
+	Patch by HJ Lu.
+	* stdlib/canonicalize.c: Likewise.
+
+	* libio/fileops.c: Change comments according to libg++2.8b5.
+	* libio/iosetvbuf.c: Follow change in libg++-2.8b5 to clear
+	unbuffered flag.
+	Reported by HJ Lu.
+
+	* manual/nss.texi: Correct prototypes.
+
+	* misc/syslog.c: Make reentrant.  Catch SIGPIPE signal to prevent
+	crash if syslog daemon is restarted.
+
+	* stdlib/rand_r.c: New file.  Implementation of POSIX.2 function
+	rand_r.
+	* stdlib/Makefile (routines): Add rand_r.
+
+	* sysdeps/stub/libc-lock.h: Define __libc_lock_trylock and
+	__libc_mutex_lock.
+
+	* configure.in: Add --disable-sanity-check option.
+	* sysdeps/unix/sysv/linux/configure.in: If linuxthreads or
+	des-crypt are not available and --disbale-sanity-check is not
+	given abort with a message.
+
+Thu Dec  5 19:19:53 1996  Richard Henderson  <rth@tamu.edu>
+
+	* posix/glob.c: Tests against STDC_HEADERS should also test
+	__GNU_LIBRARY__.
+
+Thu Dec  5 16:20:55 1996  Ulrich Drepper  <drepper@cygnus.com>
+
+	* misc/err.c (vwarn): Set errno again before using %m format.
+
+Thu Dec  5 10:14:05 1996  Andreas Jaeger  <aj@arthur.pfalz.de>
+
+	* grp/grp.h: Add declaration of __getgrent_r.
+
+	* io/fts.c (fts_build): Remove "register" from variables dirbuf
+	and dp since their address is needed.
+
+	* sysdeps/posix/getcwd.c (__getcwd): Remove "register" from
+	variable d since d's address is needed.
+
+	* misc/tst-dirname.c (main): Provide prototype.
+	* misc/ioctltst.c (main): Dito.
+
+	* Makefile: Add gnu/lib-names.h to install-others before including
+	Makerules.
+
+Wed Dec  4 16:00:09 1996  Ulrich Drepper  <drepper@cygnus.com>
+
+	* sysdeps/unix/sysv/linux/sys/socketvar.h: New file.  Simply use
+	<sys/socket.h>.
+	* sysdeps/unix/sysv/linux/Dist: Add sys/socketvar.h.
+	* sysdeps/unix/sysv/linux/Makefile [$(subdir)=inet)]: Add
+	sys/socketvar.h to sysdep_headers.
+
 Tue Dec  3 08:38:15 1996  Richard Henderson  <rth@tamu.edu>
 
 	* sysdeps/unix/alpha/sysdep.S: Remove definition of __errno_location.
@@ -125,7 +190,7 @@ Mon Dec  2 03:59:38 1996  Ulrich Drepper  <drepper@cygnus.com>
 	* sysdeps/unix/sysv/linux/gethostid.c: Likewise.
 
 	* posix/getconf.c: Treat _SC_UNIT_MAX and _SC_ULONG_MAX separately
-	since the value might be outsode the range of the `long int'.
+	since the value might be outside the range of the `long int'.
 	Print string `undefined' when a value is undefined.
 
 	* stdlib/l64a.c: Return correct pointer.
diff --git a/Makefile b/Makefile
index 1ab8945736..cd253734a6 100644
--- a/Makefile
+++ b/Makefile
@@ -90,6 +90,9 @@ echo-headers: subdir_echo-headers
 
 # What to install.
 install-others = $(includedir)/stubs.h
+ifeq (yes,$(build-shared))
+install-others += $(includedir)/gnu/lib-names.h
+endif
 
 ifeq (yes,$(gnu-ld))
 libc-init = set-init
@@ -200,8 +203,6 @@ $(includedir)/gnu/lib-names.h: $(common-objpfx)soversions.mk
 	then echo 'gnu/lib-names.h unchanged'; \
 	else $(INSTALL_DATA) $(objpfx)lib-names.h $@; fi
 	rm -f $(objpfx)lib-names.h
-
-install-others += $(includedir)/gnu/lib-names.h
 endif
 
 # This makes the Info or DVI file of the documentation from the Texinfo source.
diff --git a/configure b/configure
index 4d2a9680a6..74502074c1 100755
--- a/configure
+++ b/configure
@@ -1373,7 +1373,8 @@ else
   echo "$ac_t""no" 1>&6
 fi
 
-if test "$BASH" != no && $BASH -c 'test "$BASH_VERSINFO" -ge 2'; then
+if test "$BASH" != no &&
+   $BASH -c 'test "$BASH_VERSINFO" -ge 2 >&/dev/null'; then
   libc_cv_have_bash2=yes
 else
   libc_cv_have_bash2=no
@@ -1381,7 +1382,7 @@ fi
 
 
 echo $ac_n "checking for signed size_t type""... $ac_c" 1>&6
-echo "configure:1385: checking for signed size_t type" >&5
+echo "configure:1386: checking for signed size_t type" >&5
 if eval "test \"`echo '$''{'libc_cv_signed_size_t'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1405,12 +1406,12 @@ EOF
 fi
 
 echo $ac_n "checking for libc-friendly stddef.h""... $ac_c" 1>&6
-echo "configure:1409: checking for libc-friendly stddef.h" >&5
+echo "configure:1410: checking for libc-friendly stddef.h" >&5
 if eval "test \"`echo '$''{'libc_cv_friendly_stddef'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1414 "configure"
+#line 1415 "configure"
 #include "confdefs.h"
 #define __need_size_t
 #define __need_wchar_t
@@ -1425,7 +1426,7 @@ size_t size; wchar_t wchar;
 if (&size == NULL || &wchar == NULL) abort ();
 ; return 0; }
 EOF
-if { (eval echo configure:1429: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:1430: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   rm -rf conftest*
   libc_cv_friendly_stddef=yes
 else
@@ -1444,7 +1445,7 @@ override stddef.h = # The installed <stddef.h> seems to be libc-friendly."
 fi
 
 echo $ac_n "checking whether we need to use -P to assemble .S files""... $ac_c" 1>&6
-echo "configure:1448: checking whether we need to use -P to assemble .S files" >&5
+echo "configure:1449: checking whether we need to use -P to assemble .S files" >&5
 if eval "test \"`echo '$''{'libc_cv_need_minus_P'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1467,7 +1468,7 @@ asm-CPPFLAGS = -P # The assembler can't grok cpp's # line directives."
 fi
 
 echo $ac_n "checking for assembler global-symbol directive""... $ac_c" 1>&6
-echo "configure:1471: checking for assembler global-symbol directive" >&5
+echo "configure:1472: checking for assembler global-symbol directive" >&5
 if eval "test \"`echo '$''{'libc_cv_asm_global_directive'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1497,7 +1498,7 @@ EOF
 fi
 
 echo $ac_n "checking for .set assembler directive""... $ac_c" 1>&6
-echo "configure:1501: checking for .set assembler directive" >&5
+echo "configure:1502: checking for .set assembler directive" >&5
 if eval "test \"`echo '$''{'libc_cv_asm_set_directive'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1532,12 +1533,12 @@ fi
 
 if test $elf != yes; then
   echo $ac_n "checking for .init and .fini sections""... $ac_c" 1>&6
-echo "configure:1536: checking for .init and .fini sections" >&5
+echo "configure:1537: checking for .init and .fini sections" >&5
 if eval "test \"`echo '$''{'libc_cv_have_initfini'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1541 "configure"
+#line 1542 "configure"
 #include "confdefs.h"
 
 int main() {
@@ -1546,7 +1547,7 @@ asm (".section .init");
 				    asm (".text");
 ; return 0; }
 EOF
-if { (eval echo configure:1550: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:1551: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   rm -rf conftest*
   libc_cv_have_initfini=yes
 else
@@ -1571,19 +1572,19 @@ if test $elf = yes; then
   libc_cv_asm_underscores=no
 else
   echo $ac_n "checking for _ prefix on C symbol names""... $ac_c" 1>&6
-echo "configure:1575: checking for _ prefix on C symbol names" >&5
+echo "configure:1576: checking for _ prefix on C symbol names" >&5
 if eval "test \"`echo '$''{'libc_cv_asm_underscores'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1580 "configure"
+#line 1581 "configure"
 #include "confdefs.h"
 asm ("_glibc_foobar:");
 int main() {
 glibc_foobar ();
 ; return 0; }
 EOF
-if { (eval echo configure:1587: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest; then
+if { (eval echo configure:1588: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest; then
   rm -rf conftest*
   libc_cv_asm_underscores=yes
 else
@@ -1610,7 +1611,7 @@ if test $elf = yes; then
   libc_cv_asm_weakext_directive=no
 else
   echo $ac_n "checking for assembler .weak directive""... $ac_c" 1>&6
-echo "configure:1614: checking for assembler .weak directive" >&5
+echo "configure:1615: checking for assembler .weak directive" >&5
 if eval "test \"`echo '$''{'libc_cv_asm_weak_directive'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1633,7 +1634,7 @@ echo "$ac_t""$libc_cv_asm_weak_directive" 1>&6
 
 if test $libc_cv_asm_weak_directive = no; then
   echo $ac_n "checking for assembler .weakext directive""... $ac_c" 1>&6
-echo "configure:1637: checking for assembler .weakext directive" >&5
+echo "configure:1638: checking for assembler .weakext directive" >&5
 if eval "test \"`echo '$''{'libc_cv_asm_weakext_directive'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1670,7 +1671,7 @@ EOF
 fi
 
 echo $ac_n "checking for ld --no-whole-archive""... $ac_c" 1>&6
-echo "configure:1674: checking for ld --no-whole-archive" >&5
+echo "configure:1675: checking for ld --no-whole-archive" >&5
 if eval "test \"`echo '$''{'libc_cv_ld_no_whole_archive'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1681,7 +1682,7 @@ __throw () {}
 EOF
 if { ac_try='${CC-cc} $CFLAGS
 			    -nostdlib -nostartfiles -Wl,--no-whole-archive
-			    -o conftest conftest.c'; { (eval echo configure:1685: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }; }; then
+			    -o conftest conftest.c'; { (eval echo configure:1686: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }; }; then
   libc_cv_ld_no_whole_archive=yes
 else
   libc_cv_ld_no_whole_archive=no
@@ -1692,7 +1693,7 @@ fi
 echo "$ac_t""$libc_cv_ld_no_whole_archive" 1>&6
 
 echo $ac_n "checking for gcc -fno-exceptions""... $ac_c" 1>&6
-echo "configure:1696: checking for gcc -fno-exceptions" >&5
+echo "configure:1697: checking for gcc -fno-exceptions" >&5
 if eval "test \"`echo '$''{'libc_cv_gcc_no_exceptions'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1703,7 +1704,7 @@ __throw () {}
 EOF
 if { ac_try='${CC-cc} $CFLAGS
 			    -nostdlib -nostartfiles -fno-exceptions
-			    -o conftest conftest.c'; { (eval echo configure:1707: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }; }; then
+			    -o conftest conftest.c'; { (eval echo configure:1708: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }; }; then
   libc_cv_gcc_no_exceptions=yes
 else
   libc_cv_gcc_no_exceptions=no
@@ -1755,7 +1756,7 @@ if test "$uname" = generic; then
   fi
 
   echo $ac_n "checking OS release for uname""... $ac_c" 1>&6
-echo "configure:1759: checking OS release for uname" >&5
+echo "configure:1760: checking OS release for uname" >&5
 if eval "test \"`echo '$''{'libc_cv_uname_release'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1777,7 +1778,7 @@ echo "$ac_t""$libc_cv_uname_release" 1>&6
   uname_release="$libc_cv_uname_release"
 
   echo $ac_n "checking OS version for uname""... $ac_c" 1>&6
-echo "configure:1781: checking OS version for uname" >&5
+echo "configure:1782: checking OS version for uname" >&5
 if eval "test \"`echo '$''{'libc_cv_uname_version'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1799,7 +1800,7 @@ else
 fi
 
 echo $ac_n "checking stdio selection""... $ac_c" 1>&6
-echo "configure:1803: checking stdio selection" >&5
+echo "configure:1804: checking stdio selection" >&5
 
 case $stdio in
 libio) cat >> confdefs.h <<\EOF
diff --git a/configure.in b/configure.in
index 4a3f663cb5..3a4d200e71 100644
--- a/configure.in
+++ b/configure.in
@@ -34,7 +34,7 @@ esac
 
 dnl Arguments to specify presence of other packages/features.
 AC_ARG_WITH(fp, dnl
-  --with-fp		  if using floating-point hardware [default=yes],
+[  --with-fp		  if using floating-point hardware [default=yes]],
 	    with_fp=$withval, with_fp=yes)
 AC_ARG_WITH(gnu-binutils, dnl
   --with-gnu-binutils	  if using GNU binutils (as and ld),
@@ -59,6 +59,11 @@ AC_ARG_ENABLE(libio, dnl
 	       fi],
 	      stdio=default)
 
+AC_ARG_ENABLE(sanity-checks, dnl
+[  --disable-sanity-checks really do not use threads (should not be used
+			  except in special situations) [default=yes]],
+              enable_sanity=$enableval, enable_sanity=yes)
+
 dnl Arguments to enable or disable building the shared, profiled, and
 dnl -fomit-frame-pointer libraries.
 AC_ARG_ENABLE(shared, dnl
@@ -360,7 +365,8 @@ AC_CHECK_TOOL(AR, ar)
 AC_CHECK_TOOL(RANLIB, ranlib, :)
 
 AC_PATH_PROG(BASH, bash, no)
-if test "$BASH" != no && $BASH -c 'test "$BASH_VERSINFO" -ge 2'; then
+if test "$BASH" != no &&
+   $BASH -c 'test "$BASH_VERSINFO" -ge 2 >&/dev/null'; then
   libc_cv_have_bash2=yes
 else
   libc_cv_have_bash2=no
diff --git a/grp/grp.h b/grp/grp.h
index 3e2bd05db4..164bdd78a9 100644
--- a/grp/grp.h
+++ b/grp/grp.h
@@ -105,6 +105,8 @@ extern struct group *getgrnam __P ((__const char *__name));
    POSIX people would choose.  */
 
 #if defined(__USE_SVID) || defined (__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
+extern int __getgrent_r __P ((struct group *__resultbuf, char *buffer,
+			      size_t __buflen, struct group **__result));
 extern int getgrent_r __P ((struct group *__resultbuf, char *buffer,
 			    size_t __buflen, struct group **__result));
 #endif
diff --git a/io/fts.c b/io/fts.c
index cfc8fa656d..2a7100ec79 100644
--- a/io/fts.c
+++ b/io/fts.c
@@ -570,7 +570,7 @@ fts_build(sp, type)
 	register FTS *sp;
 	int type;
 {
-	register struct dirent dirbuf, *dp;
+	struct dirent dirbuf, *dp;
 	register FTSENT *p, *head;
 	register int nitems;
 	FTSENT *cur, *tail;
diff --git a/io/getwd.c b/io/getwd.c
index 4488cef00e..510a681d78 100644
--- a/io/getwd.c
+++ b/io/getwd.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 1991, 1992, 1996 Free Software Foundation, Inc.
+/* Obsolete function to get current working directory.
+   Copyright (C) 1991, 1992, 1996 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -21,19 +22,15 @@
 #include <string.h>
 #include <unistd.h>
 
-/* Put the absolute pathname of the current working direction in BUF.
-   If successful, return BUF.  If not, put an error message in
-   BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
+
 char *
 getwd (buf)
      char *buf;
 {
 #ifndef PATH_MAX
 #define PATH_MAX 1024
-  char fetchbuf[PATH_MAX];
-#else
-#define fetchbuf buf
 #endif
+  char tmpbuf[PATH_MAX];
 
   if (buf == NULL)
     {
@@ -41,18 +38,21 @@ getwd (buf)
       return NULL;
     }
 
-  if (getcwd (fetchbuf, PATH_MAX) == NULL)
+  if (getcwd (tmpbuf, LOCAL_PATH_MAX) == NULL)
     {
-#if defined HAVE_STRERROR_R || defined _LIBC
-      __strerror_r (errno, buf, PATH_MAX);
-#else
-      strncpy (buf, strerror (errno), PATH_MAX);
-#endif
+      /* We use 1024 here since it should really be enough and because
+	 this is a save value.  */
+      __strerror_r (errno, buf, 1024);
       return NULL;
     }
 
-  if (fetchbuf != buf)
-    strcpy (buf, fetchbuf);
+  /* This is completely unsafe.  Nobody can say how big the user
+     provided buffer is.  Perhaps the application and the libc
+     disagree about the value of PATH_MAX.  */
+  strcpy (buf, tmpbuf);
 
   return buf;
 }
+
+link_warning (getwd,
+	      "the `getwd' function is dangerous and should not be used.")
diff --git a/libio/fileops.c b/libio/fileops.c
index 1851d9a1fa..d3f4831e2d 100644
--- a/libio/fileops.c
+++ b/libio/fileops.c
@@ -45,21 +45,27 @@ extern int errno;
    is that of gptr(); in put mode that of pptr().
 
    The position in the buffer that corresponds to the position
-   in external file system is file_ptr().
-   This is normally _IO_read_end, except in putback mode,
+   in external file system is normally _IO_read_end, except in putback
+   mode, when it is _IO_save_end.
    when it is _IO_save_end.
    If the field _fb._offset is >= 0, it gives the offset in
    the file as a whole corresponding to eGptr(). (?)
 
    PUT MODE:
-   If a filebuf is in put mode, pbase() is non-NULL and equal to base().
-   Also, epptr() == ebuf().
-   Also, eback() == gptr() && gptr() == egptr().
-   The un-flushed character are those between pbase() and pptr().
+   If a filebuf is in put mode, then all of _IO_read_ptr, _IO_read_end,
+   and _IO_read_base are equal to each other.  These are usually equal
+   to _IO_buf_base, though not necessarily if we have switched from
+   get mode to put mode.  (The reason is to maintain the invariant
+   that _IO_read_end corresponds to the external file position.)
+   _IO_write_base is non-NULL and usually equal to _IO_base_base.
+   We also have _IO_write_end == _IO_buf_end, but only in fully buffered mode.
+   The un-flushed character are those between _IO_write_base and _IO_write_ptr.
+
    GET MODE:
    If a filebuf is in get or putback mode, eback() != egptr().
    In get mode, the unread characters are between gptr() and egptr().
    The OS file position corresponds to that of egptr().
+
    PUTBACK MODE:
    Putback mode is used to remember "excess" characters that have
    been sputbackc'd in a separate putback buffer.
@@ -72,7 +78,7 @@ extern int errno;
    The OS position corresponds to that of save_egptr().
 
    LINE BUFFERED OUTPUT:
-   During line buffered output, pbase()==base() && epptr()==base().
+   During line buffered output, _IO_write_base==base() && epptr()==base().
    However, ptr() may be anywhere between base() and ebuf().
    This forces a call to filebuf::overflow(int C) on every put.
    If there is more space in the buffer, and C is not a '\n',
diff --git a/libio/iosetvbuf.c b/libio/iosetvbuf.c
index 3776330a88..8ba9753efc 100644
--- a/libio/iosetvbuf.c
+++ b/libio/iosetvbuf.c
@@ -42,7 +42,7 @@ _IO_setvbuf (fp, buf, mode, size)
   switch (mode)
     {
     case _IOFBF:
-      fp->_IO_file_flags &= ~_IO_LINE_BUF;
+      fp->_IO_file_flags &= ~_IO_LINE_BUF|_IO_UNBUFFERED;
       if (buf == NULL)
 	{
 	  if (fp->_IO_buf_base == NULL)
@@ -72,6 +72,7 @@ _IO_setvbuf (fp, buf, mode, size)
 	}
       break;
     case _IOLBF:
+      fp->_IO_file_flags &= ~_IO_UNBUFFERED;
       fp->_IO_file_flags |= _IO_LINE_BUF;
       if (buf == NULL)
 	{
diff --git a/manual/nss.texi b/manual/nss.texi
index 074b85702c..4a81edca13 100644
--- a/manual/nss.texi
+++ b/manual/nss.texi
@@ -378,9 +378,9 @@ the non-reentrant and reentrant versions of our function above are:
 @smallexample
 struct hostent *gethostbyname (const char *name)
 
-struct hostent *gethostbyname_r (const char *name,
-                                 struct hostent *result_buf, char *buf,
-                                 int buflen, int *h_errnop)
+int gethostbyname_r (const char *name, struct hostent *result_buf,
+                     char *buf, size_t buflen, struct hostent **result,
+                     int *h_errnop)
 @end smallexample
 
 @noindent
@@ -389,7 +389,7 @@ The actual prototype of the function in the NSS modules in this case is
 @smallexample
 enum nss_status _nss_files_gethostbyname_r (const char *name,
                                             struct hostent *result_buf,
-                                            char *buf, int buflen,
+                                            char *buf, size_t buflen,
                                             int *h_errnop)
 @end smallexample
 
@@ -553,7 +553,7 @@ the interface.  All derive from the traditional ones for system databases.
 database (e.g., it is @code{pw} for the password database).
 
 @table @code
-@item int _nss_@var{database}_set@var{db}ent (void)
+@item enum nss_status _nss_@var{database}_set@var{db}ent (void)
 This function prepares the service for following operations.  For a
 simple file based lookup this means files could be opened, for other
 services this function simply is a noop.
@@ -566,14 +566,14 @@ argument for some @var{database}s (i.e., the interface is
 The return value should be @var{NSS_STATUS_SUCCESS} or according to the
 table above in case of an error (@pxref{NSS Modules Interface}).
 
-@item int _nss_@var{database}_end@var{db}ent (void)
+@item enum nss_status _nss_@var{database}_end@var{db}ent (void)
 This function simply closes all files which are still open or removes
 buffer caches.  If there are no files or buffers to remove this is again
 a simple noop.
 
 There normally is no return value different to @var{NSS_STATUS_SUCCESS}.
 
-@item int _nss_@var{database}_get@var{db}ent_r (@var{STRUCTURE} *result, char *buffer, int buflen)
+@item enum nss_status _nss_@var{database}_get@var{db}ent_r (@var{STRUCTURE} *result, char *buffer, size_t buflen)
 Since this function will be called several times in a row to retrieve
 one entry after the other it must keep some kind of state.  But this
 also means the functions are not really reentrant.  They are reentrant
@@ -602,7 +602,7 @@ returned.  When the service was not formerly initialized by a call to
 @code{_nss_@var{DATABASE}_set@var{db}ent} all return value allowed for
 this function can also be returned here.
 
-@item int _nss_@var{DATABASE}_get@var{db}by@var{XX}_r (@var{PARAMS}, @var{STRUCTURE} *result, char *buffer, int buflen)
+@item enum nss_status _nss_@var{DATABASE}_get@var{db}by@var{XX}_r (@var{PARAMS}, @var{STRUCTURE} *result, char *buffer, size_t buflen)
 This function shall return the entry from the database which is
 addressed by the @var{PARAMS}.  The type and number of these arguments
 vary.  It must be individually determined by looking to the user-level
diff --git a/misc/err.c b/misc/err.c
index d527573c89..56ca808bcd 100644
--- a/misc/err.c
+++ b/misc/err.c
@@ -56,6 +56,7 @@ vwarn (const char *format, __gnuc_va_list ap)
       vfprintf (stderr, format, ap);
       fputs (": ", stderr);
     }
+  __set_errno (error);
   fprintf (stderr, "%m\n");
 }
 
diff --git a/misc/ioctltst.c b/misc/ioctltst.c
index 3e8ea997eb..bf3286b650 100644
--- a/misc/ioctltst.c
+++ b/misc/ioctltst.c
@@ -10,7 +10,7 @@
  * open a socket, get the process group information of the socket, and use the
  * socket to get the network interface configuration list
  */
-main()
+main(int argc, char *argv[])
 {
   int sock;
   int ioctl_result;
@@ -26,7 +26,7 @@ main()
   /* use ioctl() to get the process group information */
   {
     int get_process_group;
-    
+
     ioctl_result = ioctl(sock, SIOCGPGRP, (char *) &get_process_group);
 
     if (ioctl_result < 0)
@@ -41,7 +41,7 @@ main()
   /* use ioctl() to get the interface configuration list */
   {
     static struct ifconf ifc;	/* init to 0 */
-    
+
     ioctl_result = ioctl(sock, SIOCGIFCONF, (char *) &ifc);
 
     if (ioctl_result < 0)
diff --git a/misc/syslog.c b/misc/syslog.c
index 9db16ca352..205909e1cd 100644
--- a/misc/syslog.c
+++ b/misc/syslog.c
@@ -49,6 +49,8 @@ static char sccsid[] = "@(#)syslog.c	8.4 (Berkeley) 3/18/94";
 #include <time.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <libc-lock.h>
+#include <signal.h>
 
 #if __STDC__
 #include <stdarg.h>
@@ -65,6 +67,14 @@ static int	LogFacility = LOG_USER;	/* default facility code */
 static int	LogMask = 0xff;		/* mask of priorities to be logged */
 extern char	*__progname;		/* Program name, from crt0. */
 
+/* Define the lock.  */
+__libc_lock_define_initialized (static, syslog_lock)
+
+static void openlog_internal(const char *, int, int);
+static void closelog_internal(void);
+static void sigpipe_handler (int);
+static void cancel_handler (void *);
+
 /*
  * syslog, vsyslog --
  *	print message on log file; output is intended for syslogd(8).
@@ -103,6 +113,9 @@ vsyslog(pri, fmt, ap)
 	char *buf = 0;
 	size_t bufsize = 0;
 	size_t prioff, msgoff;
+ 	struct sigaction action, oldaction;
+	struct sigaction *oldaction_ptr = NULL;
+ 	int sigpipe;
 
 #define	INTERNALLOG	LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 	/* Check for invalid bits. */
@@ -163,9 +176,22 @@ vsyslog(pri, fmt, ap)
 		(void)writev(STDERR_FILENO, iov, 2);
 	}
 
+	/* Prepare for multiple users.  We have to take care: open and
+	   write are cancelation points.  */
+	__libc_cleanup_region_start (cancel_handler, &oldaction_ptr);
+	__libc_lock_lock (syslog_lock);
+
+	/* Prepare for a broken connection.  */
+ 	memset (&action, 0, sizeof (action));
+ 	action.sa_handler = sigpipe_handler;
+ 	sigemptyset (&action.sa_mask);
+ 	sigpipe = sigaction (SIGPIPE, &action, &oldaction);
+	if (sigpipe == 0)
+	  oldaction_ptr = &oldaction;
+
 	/* Get connected, output the message to the local logger. */
 	if (!connected)
-		openlog(LogTag, LogStat | LOG_NDELAY, 0);
+		openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 
 	/* If we have a SOCK_STREAM connection, also send ASCII NUL as
 	   a record terminator.  */
@@ -174,7 +200,7 @@ vsyslog(pri, fmt, ap)
 
 	if (__send(LogFile, buf, bufsize, 0) < 0)
 	  {
-	    closelog ();	/* attempt re-open next time */
+	    closelog_internal ();	/* attempt re-open next time */
 	    /*
 	     * Output the message to the console; don't worry about blocking,
 	     * if console blocks everything will.  Make sure the error reported
@@ -188,15 +214,20 @@ vsyslog(pri, fmt, ap)
 	      }
 	  }
 
+	if (sigpipe == 0)
+		sigaction (SIGPIPE, &oldaction, (struct sigaction *) NULL);
+
+	/* End of critical section.  */
+	__libc_cleanup_region_end (0);
+	__libc_lock_unlock (syslog_lock);
+
 	free (buf);
 }
 
 static struct sockaddr SyslogAddr;	/* AF_UNIX address of local logger */
 
-void
-openlog(ident, logstat, logfac)
-	const char *ident;
-	int logstat, logfac;
+static void
+openlog_internal(const char *ident, int logstat, int logfac)
 {
 	if (ident != NULL)
 		LogTag = ident;
@@ -237,13 +268,60 @@ openlog(ident, logstat, logfac)
 }
 
 void
-closelog()
+openlog (const char *ident, int logstat, int logfac)
+{
+  /* Protect against multiple users.  */
+  __libc_cleanup_region_start ((void (*) __P ((void *))) __libc_mutex_unlock,
+			       &syslog_lock);
+  __libc_lock_lock (syslog_lock);
+
+  openlog_internal (ident, logstat, logfac);
+
+  /* Free the lock.  */
+  __libc_cleanup_region_end (1);
+}
+
+static void
+sigpipe_handler (int signo)
+{
+	closelog_internal();
+}
+
+static void
+closelog_internal()
 {
 	(void)close(LogFile);
 	LogFile = -1;
 	connected = 0;
 }
 
+void
+closelog ()
+{
+  /* Protect against multiple users.  */
+  __libc_cleanup_region_start ((void (*) __P ((void *))) __libc_mutex_unlock,
+			       &syslog_lock);
+  __libc_lock_lock (syslog_lock);
+
+  closelog_internal ();
+
+  /* Free the lock.  */
+  __libc_cleanup_region_end (1);
+}
+
+static void
+cancel_handler (void *ptr)
+{
+  /* Restore the old signal handler.  */
+  struct sigaction *oldaction = *((struct sigaction **) ptr);
+
+  if (oldaction != (struct sigaction *) NULL)
+    sigaction (SIGPIPE, oldaction, (struct sigaction *) NULL);
+
+  /* Free the lock.  */
+  __libc_lock_unlock (syslog_lock);
+}
+
 /* setlogmask -- set the log mask level */
 int
 setlogmask(pmask)
diff --git a/misc/tst-dirname.c b/misc/tst-dirname.c
index 78eb1b5db0..472c290789 100644
--- a/misc/tst-dirname.c
+++ b/misc/tst-dirname.c
@@ -43,7 +43,9 @@ test (input, result)
 }
 
 int
-main ()
+main (argc, argv)
+     int argc;
+     char *argv[];
 {
   int result = 0;
 
diff --git a/posix/glob.c b/posix/glob.c
index 5dab2f2e1e..ba5f2368f3 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -52,7 +52,7 @@
 
 #ifndef ELIDE_CODE
 
-#ifdef	STDC_HEADERS
+#if defined(STDC_HEADERS) || defined(__GNU_LIBRARY__)
 #include <stddef.h>
 #endif
 
@@ -222,7 +222,7 @@ extern char *alloca ();
 #endif
 #endif
 
-#ifndef	STDC_HEADERS
+#if !(defined (STDC_HEADERS) || defined (__GNU_LIBRARY__))
 #undef	size_t
 #define	size_t	unsigned int
 #endif
diff --git a/stdlib/Makefile b/stdlib/Makefile
index 66f28ffe5c..9d5744fc78 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -32,7 +32,7 @@ routines	:=							      \
 	abs labs llabs							      \
 	div ldiv lldiv							      \
 	mblen mbstowcs mbtowc wcstombs wctomb				      \
-	random random_r rand 						      \
+	random random_r rand rand_r					      \
 	drand48 erand48 lrand48 nrand48 mrand48 jrand48			      \
 	srand48 seed48 lcong48						      \
 	drand48_r erand48_r lrand48_r nrand48_r mrand48_r jrand48_r	      \
diff --git a/stdlib/canonicalize.c b/stdlib/canonicalize.c
index 554e1b2cba..8c0074a11c 100644
--- a/stdlib/canonicalize.c
+++ b/stdlib/canonicalize.c
@@ -1,21 +1,21 @@
 /* Return the canonical absolute name of a given file.
-Copyright (C) 1996 Free Software Foundation, Inc.
-This file is part of the GNU C Library.
+   Copyright (C) 1996 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
 
-The GNU C Library is free software; you can redistribute it and/or
-modify it under the terms of the GNU Library General Public License as
-published by the Free Software Foundation; either version 2 of the
-License, or (at your option) any later version.
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
 
-The GNU C Library is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-Library General Public License for more details.
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
 
-You should have received a copy of the GNU Library General Public
-License along with the GNU C Library; see the file COPYING.LIB.  If
-not, write to the Free Software Foundation, Inc., 675 Mass Ave,
-Cambridge, MA 02139, USA.  */
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
 
 #include <assert.h>
 #include <stdlib.h>
@@ -58,10 +58,22 @@ canonicalize (const char *name, char *resolved)
   if (!resolved)
     rpath = malloc (path_max);
 
-  strcpy (rpath, "/");
-  if (name[0] != '/' && !getcwd (rpath, path_max))
-    goto error;
-  dest = rpath + strlen (rpath);
+  if (name[0] != '/')
+    {
+      /* We don't write to RPATH directly since the application and
+	 the library might disagree about the value for PATH_MAX.  */
+      char tmpbuf[path_max];
+
+      if (!getcwd (rpath, path_max))
+	goto error;
+
+      dest = __stpcpy (rpath, tmpbuf);
+    }
+  else
+    {
+      rpath[0] = '/';
+      dest = rpath + 1;
+    }
 
   for (start = end = name; *start; start = end)
     {
@@ -164,9 +176,9 @@ error:
     free (rpath);
   return NULL;
 }
-
 weak_alias (canonicalize, realpath)
 
+
 char *
 canonicalize_file_name (const char *name)
 {
diff --git a/sysdeps/unix/sysv/linux/alpha/llseek.S b/stdlib/rand_r.c
index a2e644c161..3e0b8b2bc0 100644
--- a/sysdeps/unix/sysv/linux/alpha/llseek.S
+++ b/stdlib/rand_r.c
@@ -1,6 +1,7 @@
-/* Copyright (C) 1993, 1995, 1996 Free Software Foundation, Inc.
+/* Reentrant random function frm POSIX.1c.
+   Copyright (C) 1996 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
-   Contributed by David Mosberger <davidm@cs.arizona.edu>, 1995.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public License as
@@ -17,44 +18,32 @@
    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.  */
 
-/* For compatibility only: a "long" is 64 bits on the Alpha, so
-   llseek() isn't really needed.  But there are some programs out
-   there who may depend on it being around.  */
-
-#include <sysdep.h>
-
-	.text
-ENTRY(llseek)
-#ifdef PROF
-	ldgp	gp, 0(pv)
-	.set noat
-	lda	AT, _mcount
-	jsr	AT, (AT), _mcount
-	.set at
-	.prologue 1
-#else
-	.prologue 0
-#endif
-
-	sll	a1, 32, a1	/* build a 64 bit ofs out of 32 bit operands */
-	zap	a2, 0xf0, a2
-	mov	a3, t0		/* save result address */
-	bis	a2, a1, a1
-
-	mov	a4, a2		/* shift down whence */
-
-	ldi	v0, __NR_lseek
-	call_pal PAL_callsys
-	bne	a3, error
-
-	stq	v0, 0(t0)
-	ret
-
-error:
-#ifndef PROF
-	br	gp, 1f
-1:	ldgp	gp, 0(gp)
-#endif
-	jmp	zero, __syscall_error
-
-	END(llseek)
+#include <stdlib.h>
+
+
+/* This algorithm is mentioned in the ISO C standard, here extended
+   for 32 bits.  */
+int
+rand_r (unsigned int *seed)
+{
+  unsigned int next = *seed;
+  int result;
+
+  next *= 1103515245;
+  next += 12345;
+  result = (unsigned int) (next / 65536) % 2048;
+
+  next *= 1103515245;
+  next += 12345;
+  result <<= 11;
+  result ^= (unsigned int) (next / 65536) % 1024;
+
+  next *= 1103515245;
+  next += 12345;
+  result <<= 10;
+  result ^= (unsigned int) (next / 65536) % 1024;
+
+  *seed = next;
+
+  return result;
+}
diff --git a/sysdeps/posix/getcwd.c b/sysdeps/posix/getcwd.c
index 92196ac50a..4ea90a7320 100644
--- a/sysdeps/posix/getcwd.c
+++ b/sysdeps/posix/getcwd.c
@@ -253,7 +253,7 @@ __getcwd (buf, size)
   while (!(thisdev == rootdev && thisino == rootino))
     {
       register DIR *dirstream;
-      register struct dirent *d;
+      struct dirent *d;
 #if defined HAVE_READDIR_R || defined _LIBC
       struct dirent dirbuf;
 #endif
diff --git a/sysdeps/stub/libc-lock.h b/sysdeps/stub/libc-lock.h
index 158a221718..d0a82fea21 100644
--- a/sysdeps/stub/libc-lock.h
+++ b/sysdeps/stub/libc-lock.h
@@ -48,6 +48,9 @@
 /* Lock the named lock variable.  */
 #define __libc_lock_lock(NAME)
 
+/* Try tp lock the named lock variable.  */
+#define __libc_lock_trylock(NAME)
+
 /* Unlock the named lock variable.  */
 #define __libc_lock_unlock(NAME)
 
@@ -58,4 +61,7 @@
 #define __libc_cleanup_region_end(DOIT)
 
 
+/* We need protable names for some of the functions.  */
+#define __libc_mutex_unlock
+
 #endif	/* libc-lock.h */
diff --git a/sysdeps/unix/sysv/linux/Dist b/sysdeps/unix/sysv/linux/Dist
index 0adc370632..40f65b838c 100644
--- a/sysdeps/unix/sysv/linux/Dist
+++ b/sysdeps/unix/sysv/linux/Dist
@@ -22,6 +22,7 @@ sys/mtio.h
 sys/procfs.h
 sys/quota.h
 sys/socketcall.h
+sys/socketvar.h
 sys/soundcard.h
 sys/sysctl.h
 sys/sysinfo.h
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index c7cf1f9570..c03d966a61 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -51,7 +51,7 @@ inhibit-siglist := yes
 endif
 
 ifeq ($(subdir), inet)
-sysdep_headers += netinet/in_systm.h
+sysdep_headers += netinet/in_systm.h sys/socketvar.h
 endif
 
 # Don't compile the ctype glue code, since there is no old non-GNU C library.
diff --git a/sysdeps/unix/sysv/linux/configure b/sysdeps/unix/sysv/linux/configure
index ef7590d367..867d4fbe7a 100644
--- a/sysdeps/unix/sysv/linux/configure
+++ b/sysdeps/unix/sysv/linux/configure
@@ -1,39 +1,16 @@
- # Local configure fragment for sysdeps/unix/sysv/linux.
-
-# On Linux, the default is to use libio instead of stdio.
-test $stdio = default && stdio=libio
-
-# Don't bother trying to generate any glue code to be compatible with the
-# existing system library, because we are the only system library.
-inhibit_glue=yes
-
-echo $ac_n "checking installed Linux kernel header files""... $ac_c" 1>&6
-if eval "test \"`echo '$''{'libc_cv_linux2010'+set}'`\" = set"; then
-  echo $ac_n "(cached) $ac_c" 1>&6
-else
-  cat > conftest.$ac_ext <<EOF
-#line 16 "configure"
-#include "confdefs.h"
-#include <linux/version.h>
-int main() { return 0; }
-int t() {
-#if LINUX_VERSION_CODE <  (2 *65536+ 0 *256+ 10) /* 2.0.10 */
-eat flaming death
-#endif
-; return 0; }
-EOF
-if { (eval echo configure:26: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+; then
   rm -rf conftest*
   libc_cv_linux2010='2.0.10 or later'
 else
+  echo "configure: failed program was:" >&AC_FD_CC
+  cat conftest.$ac_ext >&AC_FD_CC
   rm -rf conftest*
   libc_cv_linux2010='TOO OLD!'
 fi
 rm -f conftest*
-
 fi
 
-echo "$ac_t""$libc_cv_linux2010" 1>&6
+echo "$ac_t""$libc_cv_linux2010" 1>&AC_FD_MSG
 if test "$libc_cv_linux2010" != '2.0.10 or later'; then
   { echo "configure: error: GNU libc requires kernel header files from
 Linux 2.0.10 or later to be installed before configuring.
@@ -57,20 +34,36 @@ fi
 case $add_ons in
   # Both are available.  Good.
   *linuxthreads*des-crypt* | *des-crypt*linuxthreads*)
+    message=
     ;;
   *linuxthreads*)
-    echo "\
+    message="\
 *** WARNING:
 *** Are you sure you do not want to use the \`crypt' add-on?"
     ;;
   *des-crypt*)
-    echo "\
+    message="\
 *** WARNING:
 *** Are you sure you do not want to use the \`LinuxThread' add-on?"
     ;;
   *)
-    echo "\
+    message="\
 *** WARNING: Are you sure you do not want to use the \`LinuxThreads'
 *** and \`crypt' add-ons?"
     ;;
 esac
+
+if test "$message"; then
+  if test $enable_sanity = yes; then
+    echo "\
+*** You should not compile the GNU libc without the \`LinuxThreads' and
+*** \`crypt' add-on.  Not using them risks to be incompatible with the
+*** libraries of other systems.  Consider getting the add-ons and restart
+*** the configuration.
+*** If you really mean to avoid those add-ons run configure again, now
+*** using the extra parameter \`--disable-sanity-checks'."
+    exit 1
+  else
+    echo "$message"
+  fi
+fi
diff --git a/sysdeps/unix/sysv/linux/configure.in b/sysdeps/unix/sysv/linux/configure.in
index c4937923a9..b6474a940c 100644
--- a/sysdeps/unix/sysv/linux/configure.in
+++ b/sysdeps/unix/sysv/linux/configure.in
@@ -29,3 +29,50 @@ Linux LIBC_LINUX_VERSION or later.  This check uses <linux/version.h>, so
 make sure that file was built correctly when installing the kernel header
 files.])
 fi
+
+# The Linux filesystem standard prescribes where to place "essential"
+# files.  I.e., when the installation prefix is "/usr" we have to place
+# shared library objects and the configuation files on the root partition
+# in /lib and /etc.
+if test "$prefix" = "/usr"; then
+  libc_cv_slibdir="/lib"
+  libc_cv_sysconfdir="/etc"
+fi
+
+# Under Linux the LinuxThreads and crypt add-on should be available.
+case $add_ons in
+  # Both are available.  Good.
+  *linuxthreads*des-crypt* | *des-crypt*linuxthreads*)
+    message=
+    ;;
+  *linuxthreads*)
+    message="\
+*** WARNING:
+*** Are you sure you do not want to use the \`crypt' add-on?"
+    ;;
+  *des-crypt*)
+    message="\
+*** WARNING:
+*** Are you sure you do not want to use the \`LinuxThread' add-on?"
+    ;;
+  *)
+    message="\
+*** WARNING: Are you sure you do not want to use the \`LinuxThreads'
+*** and \`crypt' add-ons?"
+    ;;
+esac
+
+if test "$message"; then
+  if test $enable_sanity = yes; then
+    echo "\
+*** You should not compile the GNU libc without the \`LinuxThreads' and
+*** \`crypt' add-on.  Not using them risks to be incompatible with the
+*** libraries of other systems.  Consider getting the add-ons and restart
+*** the configuration.
+*** If you really mean to avoid those add-ons run configure again, now
+*** using the extra parameter \`--disable-sanity-checks'."
+    exit 1
+  else
+    echo "$message"
+  fi
+fi
diff --git a/sysdeps/unix/sysv/linux/sys/socketvar.h b/sysdeps/unix/sysv/linux/sys/socketvar.h
new file mode 100644
index 0000000000..3945db124a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sys/socketvar.h
@@ -0,0 +1,3 @@
+/* This header is used on many systems but for Linux we have everything
+   already defined in the standard header.  */
+#include <sys/socket.h>