Remove add-ons mechanism.

glibc has an add-ons mechanism to allow additional software to be
integrated into the glibc build.  Such add-ons may be within the glibc
source tree, or outside it at a path passed to the --enable-add-ons
configure option.

localedata and crypt were once add-ons, distributed in separate
release tarballs, but long since stopped using that mechanism.
Linuxthreads was always an add-on.  Ports spent some time as an add-on
with separate release tarballs, then was first moved into the glibc
source tree, then had its sysdeps files moved into the main sysdeps
hierarchy so the add-ons mechanism was no longer used.  NPTL spent
some time as an add-on in the main glibc tree before stopping using
the add-on mechanism.  libidn used to have separate release tarballs
but no longer does so, but still uses the add-ons mechanism within the
glibc source tree.  Various other software has supported building with
the add-ons mechanism at times in the past, but I don't think any is
still widely used.

Add-ons involve significant, little-used complexity in the glibc build
system, and make it hard to understand what the space of possible
glibc configurations is.  This patch removes the add-ons mechanism.
libidn is now built via the Subdirs mechanism to cause any
configuration using sysdeps/unix/inet to build libidn; HAVE_LIBIDN
(which effectively means shared libraries are available) is now
defined via sysdeps/unix/inet/configure.  Various references to
add-ons around the source tree are removed (in the case of maint.texi,
the example list of sysdeps directories is still very out of date).

Externally maintained ports should now put their files in the normal
sysdeps directory structure rather than being arranged as add-ons;
they probably need to change e.g. elf.h anyway, rather than actually
being able to work just as a drop-in subtree.  Hurd libpthread should
be arranged similarly to NPTL, so some files might go in a
hurd-pthreads (or similar) top-level directory in glibc, while sysdeps
files should go in the normal sysdeps directory structure (possibly in
hurd or hurd-pthreads subdirectories, just as there are nptl
subdirectories in the sysdeps tree).

Tested for x86_64, and with build-many-glibcs.py.

	* configure.ac (--enable-add-ons): Remove option.
	(machine): Do not mention add-ons in comment.
	(LIBC_PRECONFIGURE): Likewise.
	(add_ons): Remove variable and sanity checks and logic to locate
	add-ons.
	(add_ons_automatic): Remove variable.
	(configured_add_ons): Likewise.
	(add_ons_sfx): Likewise.
	(add_ons_pfx): Likewise.
	(add_on_subdirs): Likewise.
	(sysnames_add_ons): Likewise.  Remove loop over add-ons and
	consideration of add-ons in Implies handling.
	(sysdeps_add_ons): Likewise.
	* configure: Regenerated.
	* libidn/configure.ac: Remove.
	* libidn/configure: Likewise.
	* sysdeps/unix/inet/configure.ac: New file.
	* sysdeps/unix/inet/configure: New generated file.
	* sysdeps/unix/inet/Subdirs: Add libidn.
	* Makeconfig (sysdeps-srcdirs): Remove variable.
	(+sysdep_dirs): Do not include $(sysdeps-srcdirs).
	($(common-objpfx)config.status): Do not depend on add-on files.
	($(common-objpfx)shlib-versions.v.i): Do not mention add-ons in
	comment.
	(all-subdirs): Do not include $(add-on-subdirs).
	* Makefile (dist-prepare): Do not use $(sysdeps-add-ons).
	* config.make.in (add-ons): Remove variable.
	(add-on-subdirs): Likewise.
	(sysdeps-add-ons): Likewise.
	* manual/Makefile (add-chapters): Remove.
	($(objpfx)texis): Do not depend on $(add-chapters).
	(nonexamples): Do not handle $(add-chapters).
	(examples): Do not handle $(add-ons).
	(chapters.% top-menu.%): Do not pass '$(add-chapters)' to
	libc-texinfo.sh.
	* manual/install.texi (Installation): Do not mention add-ons.
	(--enable-add-ons): Do not document configure option.
	* INSTALL: Regenerated.
	* manual/libc-texinfo.sh: Do not handle $2 add-ons argument.
	* manual/maint.texi (Hierarchy Conventions): Do not mention
	add-ons.
	* scripts/build-many-glibcs.py (Glibc.build_glibc): Do not use
	--enable-add-ons.
	* scripts/gen-sorted.awk: Do not handle Subdirs files from
	add-ons.
	* scripts/test-installation.pl: Do not handle glibc-compat add-on.
	* sysdeps/nptl/Makeconfig: Do not mention add-ons in comment.

1 files changed, 27 insertions, 241 deletions

diff --git a/configure.ac b/configure.ac
index 4b83ae5a09..195e81acfd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -209,13 +209,6 @@ if test "$enable_lock_elision" = yes ; then
   AC_DEFINE(ENABLE_LOCK_ELISION)
 fi
 
-dnl Generic infrastructure for drop-in additions to libc.
-AC_ARG_ENABLE([add-ons],
-	      AC_HELP_STRING([--enable-add-ons@<:@=DIRS...@:>@],
-			     [configure and build add-ons in DIR1,DIR2,...
-			      search for add-ons if no parameter given]),
-			     , [enable_add_ons=yes])
-
 AC_ARG_ENABLE([hidden-plt],
 	      AC_HELP_STRING([--disable-hidden-plt],
 			     [do not hide internal function calls to avoid PLT]),
@@ -483,7 +476,7 @@ config_os="`echo $config_os | sed 's/^unknown-//'`"
 # Some configurations imply other options.
 elf=yes
 
-# The configure fragment of an add-on port can modify these to supplement
+# The configure fragment of a port can modify these to supplement
 # or override the table in the case statement below.  No fragment should
 # ever change the config_* variables, however.
 machine=$config_machine
@@ -506,138 +499,9 @@ AC_ARG_WITH([cpu],
 # check below.
 libc_config_ok=no
 
-dnl Let sysdeps/*/preconfigure act here, like they can in add-ons.
+dnl Let sysdeps/*/preconfigure act here.
 LIBC_PRECONFIGURE([$srcdir], [for sysdeps])
 
-dnl Having this here, though empty, makes sure that if add-ons' fragments
-dnl do AC_CONFIG_SUBDIRS([some-dir]), which just sets $subdirs, then
-dnl our AC_OUTPUT will actually use it.
-AC_CONFIG_SUBDIRS()
-
-case "$enable_add_ons" in
-''|no) add_ons= ;;
-yes|'*')
- add_ons=`cd $srcdir && ls -d 2> /dev/null */configure */sysdeps |
-	  sed 's@/[[^/]]*$@@' | sort | uniq`
-	 add_ons_automatic=yes
-	 ;;
-*) add_ons=`echo "$enable_add_ons" | sed 's/,/ /g'`
-       add_ons_automatic=no ;;
-esac
-
-configured_add_ons=
-add_ons_sfx=
-add_ons_pfx=
-if test x"$add_ons" != x; then
-  for f in $add_ons; do
-    # Some sanity checks
-    case "$f" in
-    crypt)
-      AC_MSG_ERROR([
-*** It seems that you're using an old \`crypt' add-on.  crypt is now
-*** part of glibc and using the old add-on will not work with this
-*** release.  Start again with fresh sources and without the old
-*** \`crypt' add-on.])
-    ;;
-    localedata)
-      AC_MSG_ERROR([
-*** It seems that you're using an old \`localedata' add-on.  localedata
-*** is now part of glibc and using the old add-on will not work with
-*** this release.  Start again with fresh sources and without the old
-*** \`localedata' add-on.])
-    ;;
-    esac
-  done
-
-  # Now source each add-on's configure fragment.
-  # The fragments can use $srcdir/$libc_add_on to find themselves,
-  # and test $add_ons_automatic to see if they were explicitly requested.
-  # A fragment can clear (or even change) $libc_add_on to affect
-  # whether it goes into the list to be actually used in the build.
-  use_add_ons=
-  for libc_add_on in $add_ons; do
-    # Test whether such a directory really exists.
-    # It can be absolute, or relative to $srcdir, or relative to the build dir.
-    case "$libc_add_on" in
-    /*)
-      libc_add_on_srcdir=$libc_add_on
-      ;;
-    *)
-      test -d "$srcdir/$libc_add_on" || {
-	if test -d "$libc_add_on"; then
-	  libc_add_on="`pwd`/$libc_add_on"
-	else
-	  AC_MSG_ERROR(add-on directory \"$libc_add_on\" does not exist)
-	fi
-      }
-      libc_add_on_srcdir=$srcdir/$libc_add_on
-      ;;
-    esac
-
-    libc_add_on_frag=$libc_add_on_srcdir/configure
-    libc_add_on_canonical=
-    libc_add_on_config_subdirs=
-    if test -r "$libc_add_on_frag"; then
-      AC_MSG_NOTICE(running configure fragment for add-on $libc_add_on)
-      libc_add_on_canonical=unknown
-      libc_add_on_subdirs=
-      . "$libc_add_on_frag"
-      test -z "$libc_add_on" || {
-	configured_add_ons="$configured_add_ons $libc_add_on"
-	if test "x$libc_add_on_canonical" = xunknown; then
-	  AC_MSG_ERROR(fragment must set \$libc_add_on_canonical)
-	fi
-	for d in $libc_add_on_subdirs; do
-	  case "$libc_add_on" in
-	  /*) subdir_srcdir="$libc_add_on" ;;
-	  *) subdir_srcdir="\$(..)$libc_add_on" ;;
-	  esac
-	  case "$d" in
-	  .)
-	    d="${libc_add_on_canonical:-$libc_add_on}"
-	    ;;
-	  /*)
-	    subdir_srcdir="$d"
-	    ;;
-	  *)
-	    subdir_srcdir="$subdir_srcdir/$d"
-	    ;;
-	  esac
-	  d=`echo "$d" | sed 's@/*$@@;s@^.*/@@'`
-	  add_on_subdirs="$add_on_subdirs $d"
-	  test "$subdir_srcdir" = "\$(..)$d" || config_vars="$config_vars
-$d-srcdir = $subdir_srcdir"
-	done
-	for d in $libc_add_on_config_subdirs; do
-	  case "$d" in
-	  /*) AC_MSG_ERROR(dnl
-fragment uses absolute path in \$libc_add_on_config_subdirs) ;;
-	  esac
-	  if test ! -d "$libc_add_on_srcdir/$d"; then
-	    AC_MSG_ERROR(fragment wants to configure missing directory $d)
-	  fi
-	  case "$libc_add_on" in
-	  /*) AC_MSG_ERROR(dnl
-relative path required for add-on using \$libc_add_on_config_subdirs) ;;
-	  esac
-	  subdirs="$subdirs $libc_add_on/$d"
-	done
-      }
-    fi
-    if test -n "$libc_add_on"; then
-      LIBC_PRECONFIGURE([$libc_add_on_srcdir], [add-on $libc_add_on for])
-      use_add_ons="$use_add_ons $libc_add_on"
-      add_ons_pfx="$add_ons_pfx $libc_add_on/"
-      test -z "$libc_add_on_canonical" ||
-      add_ons_sfx="$add_ons_sfx /$libc_add_on_canonical"
-    fi
-  done
-  # Use echo to strip excess whitespace.
-  add_ons="`echo $use_add_ons`"
-fi
-AC_SUBST(add_ons)
-AC_SUBST(add_on_subdirs)
-
 
 ###
 ### By using the undocumented --enable-hacker-mode option for configure
@@ -853,7 +717,6 @@ dnl We are done with glob and regexp uses of [ and ]; return to autoconf.
 changequote([,])dnl
 
 # Find what sysdep directories exist.
-sysnames_add_ons=
 sysnames=
 for b in $base ''; do
   for m0 in $mach ''; do
@@ -862,34 +725,21 @@ for b in $base ''; do
       for o in /$ostry ''; do
 	test "$o" = / && continue
 	for m in $mach ''; do
-	  for d in $add_ons_pfx ''; do
-	    for a in $add_ons_sfx ''; do
-	      try_suffix="$m0$b$v$o$m"
-	      if test -n "$try_suffix"; then
-		try_srcdir="${srcdir}/"
-		case "$d" in
-		/*) try_srcdir= ;;
-		esac
-		try="${d}sysdeps$try_suffix$a"
-		test -n "$enable_debug_configure" &&
-		echo "$0 [DEBUG]: try $try" >&2
-		if test -d "$try_srcdir$try"; then
-		  sysnames="$sysnames $try"
-		  { test -n "$o" || test -n "$b"; } && os_used=t
-		  { test -n "$m" || test -n "$m0"; } && machine_used=t
-		  case x${m0:-$m} in
-		  x*/$submachine) submachine_used=t ;;
-		  esac
-		  if test -n "$d"; then
-		    case "$sysnames_add_ons" in
-		    *" $d "*) ;;
-		    *|'') sysnames_add_ons="$sysnames_add_ons $d" ;;
-		    esac
-		  fi
-		fi
-	      fi
-	    done
-	  done
+	  try_suffix="$m0$b$v$o$m"
+	  if test -n "$try_suffix"; then
+	    try_srcdir="${srcdir}/"
+	    try="sysdeps$try_suffix"
+	    test -n "$enable_debug_configure" &&
+	    echo "$0 [DEBUG]: try $try" >&2
+	    if test -d "$try_srcdir$try"; then
+	      sysnames="$sysnames $try"
+	      { test -n "$o" || test -n "$b"; } && os_used=t
+	      { test -n "$m" || test -n "$m0"; } && machine_used=t
+	      case x${m0:-$m} in
+	      x*/$submachine) submachine_used=t ;;
+	      esac
+	    fi
+	  fi
 	done
       done
     done
@@ -898,7 +748,7 @@ done
 
 # If the assembler supports gnu_indirect_function symbol type and the
 # architecture supports multi-arch, we enable multi-arch by default.
-case $sysnames_add_ons$sysnames in
+case $sysnames in
 *"$multi_arch_d"*)
   ;;
 *)
@@ -960,24 +810,15 @@ while test $# -gt 0; do
 	  eval "${implies_type}=\"\$${implies_type} \$name_base/\$x\""
 	  found=yes
 	fi
-	for d in $add_ons_pfx ''; do
-	  try="${d}sysdeps/$x"
-	  case $d in
-	   /*) try_srcdir= ;;
-	   *) try_srcdir=$srcdir/ ;;
-	  esac
-	  test -n "$enable_debug_configure" &&
-	   echo "[DEBUG]: $name $implies_file $x try($d) {$try_srcdir}$try" >&2
-	  if test $try != $xsrcdir$name_base/$x && test -d $try_srcdir$try;
-	  then
-	    eval "${implies_type}=\"\$${implies_type} \$try\""
-	    found=yes
-	    case "$sysnames_add_ons" in
-	    *" $d "*) ;;
-	    *|'') sysnames_add_ons="$sysnames_add_ons $d" ;;
-	    esac
-	  fi
-	done
+	try="sysdeps/$x"
+	try_srcdir=$srcdir/
+	test -n "$enable_debug_configure" &&
+	 echo "[DEBUG]: $name $implies_file $x try() {$try_srcdir}$try" >&2
+	if test $try != $xsrcdir$name_base/$x && test -d $try_srcdir$try;
+	then
+	  eval "${implies_type}=\"\$${implies_type} \$try\""
+	  found=yes
+	fi
 	if test $found = no; then
 	  AC_MSG_WARN($name/$implies_file specifies nonexistent $x)
 	fi
@@ -1015,61 +856,6 @@ AC_SUBST(sysnames)
 # The other names were emitted during the scan.
 AC_MSG_RESULT($default_sysnames)
 
-# Collect the list of add-ons that supply partial sysdeps trees.
-sysdeps_add_ons=
-for add_on in $add_ons; do
-  case "$add_on" in
-  /*) xsrcdir= ;;
-  *) xsrcdir="$srcdir/" ;;
-  esac
-
-  test -d "$xsrcdir$add_on/sysdeps" || {
-    case "$configured_add_ons " in
-    *" $add_on "*) ;;
-    *|'')
-      AC_MSG_ERROR(add-on $add_on has no configure fragment or sysdeps tree)
-      ;;
-    esac
-    continue
-  }
-
-  sysdeps_add_ons="$sysdeps_add_ons $add_on"
-  case "$sysnames_add_ons" in
-  *" $add_on/ "*) ;;
-  *|'')
-    AC_MSG_WARN(add-on $add_on contributed no sysdeps directories)
-    continue ;;
-  esac
-
-  found=no
-  for d in $sysnames; do
-    case "$d" in
-    $add_on/sysdeps/*) ;;
-    *) continue ;;
-    esac
-    (cd "$xsrcdir$d" && for f in *[[!~]]; do
-       case "$f" in
-       sys|bits)
-	 for ff in $f/*.h; do
-	   test -d "$ff" || { test -e "$ff" && exit 88; }
-	 done
-	 ;;
-       *)
-	 test -d "$f" || { test -e "$f" && exit 88; }
-	 ;;
-       esac
-     done)
-    if test $? -eq 88; then
-      found=yes
-      break
-    fi
-  done
-  if test $found = no; then
-    AC_MSG_WARN(add-on $add_on contributed no useful sysdeps directories)
-  fi
-done
-AC_SUBST(sysdeps_add_ons)
-
 
 ### Locate tools.