Don't install libio.h or _G_config.h.

We shipped 2.27 with libio.h and _G_config.h still installed but
issuing warnings when used.  Let's stop installing them early in 2.28
so that we have plenty of time to think of another plan if there are
problems.

The public stdio.h had a genuine dependency on libio.h for the
complete definitions of FILE and cookie_io_functions_t, and a genuine
dependency on _G_config.h for the complete definitions of fpos_t and
fpos64_t; these are moved to single-type headers.
bits/types/struct_FILE.h also provides a handful of accessor and
bitflags macros so that code is not duplicated between bits/stdio.h
and libio.h.  All the other _IO_ and _G_ names used by the public
stdio.h can be replaced with either public names or __-names.

In order to minimize the risk of breaking our own compatibility code,
bits/types/struct_FILE.h preserves the _IO_USE_OLD_IO_FILE mechanism
exactly as it was in libio.h, but you have to define _LIBC to use it,
or it'll error out.  Similarly, _IO_lock_t_defined is preserved
exactly, but will error out if used without defining _LIBC.

Internally, include/stdio.h continues to include libio.h, and libio.h
scrupulously provides every _IO_* and _G_* name that it always did,
perhaps now defined in terms of the public names.  This is how this
patch avoids touching dozens of files throughout glibc and becoming
entangled with the _IO_MTSAFE_IO mess.  The remaining patches in this
series eliminate most of the _G_ names.

Tested on x86_64-linux; in addition to the test suite, I installed the
library in a sysroot and verified that a simple program that uses
stdio.h could be compiled against the installed library, and I also
verified that installed stripped libraries are unchanged.

	* libio/bits/types/__fpos_t.h, libio/bits/types/__fpos64_t.h:
	New single-type headers split from _G_config.h.
	* libio/bits/types/cookie_io_functions_t.h
	* libio/bits/types/struct_FILE.h
	New single-type headers split from libio.h.

	* libio/Makefile: Install the above new headers.  Don't install
	libio.h, _G_config.h, bits/libio.h, bits/_G_config.h, or
	bits/libio-ldbl.h.
	* libio/_G_config.h, libio/libio.h: Delete file.

	* libio/bits/libio.h: Remove improper-inclusion guard.
	Include stdio.h and don't repeat anything that it does.
	Define _IO_fpos_t as __fpos_t, _IO_fpos64_t as __fpos64_t,
	_IO_BUFSIZ as BUFSIZ, _IO_va_list as __gnuc_va_list,
	__io_read_fn as cookie_read_function_t,
	__io_write_fn as cookie_write_function_t,
	__io_seek_fn as cookie_seek_function_t,
	__io_close_fn as cookie_close_function_t,
	and _IO_cookie_io_functions_t as cookie_io_functions_t.
	Define _STDIO_USES_IOSTREAM, __HAVE_COLUMN, and _IO_file_flags
	here, in the "compatibility defines" section.  Remove an #if 0
	block.  Use the "body" macros from bits/types/struct_FILE.h to
	define _IO_getc_unlocked, _IO_putc_unlocked, _IO_feof_unlocked,
	and _IO_ferror_unlocked.
	Move prototypes of __uflow and __overflow...

	* libio/stdio.h: ...here.  Don't include bits/libio.h.
	Don't define _STDIO_USES_IOSTREAM.  Get __gnuc_va_list
	directly from stdarg.h.  Include bits/types/__fpos_t.h,
	bits/types/__fpos64_t.h, bits/types/struct_FILE.h,
	and, when __USE_GNU, bits/types/cookie_io_functions_t.h.
	Use __gnuc_va_list, not _G_va_list; __fpos_t, not _G_fpos_t;
	__fpos64_t, not _G_fpos64_t; FILE, not struct _IO_FILE;
	cookie_io_functions_t, not _IO_cookie_io_functions_t;
	__ssize_t, not _IO_ssize_t.  Unconditionally define
	BUFSIZ as 8192 and EOF as (-1).

	* libio/bits/stdio.h: Add multiple-include guard.  Use the "body"
	macros from bits/types/struct_FILE.h instead of _IO_* macros
	from libio.h; use __gnuc_va_list instead of va_list and __ssize_t
	instead of _IO_ssize_t.
	* libio/bits/stdio2.h: Similarly.

	* libio/iolibio.h: Add multiple-include guard.
	Include bits/libio.h after stdio.h.
	* libio/libioP.h: Add multiple-include guard.
	Include stdio.h and bits/libio.h before iolibio.h.

        * include/bits/types/__fpos_t.h, include/bits/types/__fpos64_t.h
	* include/bits/types/cookie_io_functions_t.h
	* include/bits/types/struct_FILE.h: New wrappers.

	* bits/_G_config.h, sysdeps/unix/sysv/linux/_G_config.h:
        Get definitions of _G_fpos_t and _G_fpos64_t from
        bits/types/__fpos_t.h and bits/types/__fpos64_t.h
        respectively.  Remove improper-inclusion guards.

        * conform/data/stdio.h-data: Update expectations of va_list.
	* scripts/check-installed-headers.sh: Remove special case for
        libio.h and _G_config.h.

4 files changed, 215 insertions, 0 deletions

diff --git a/libio/bits/types/__fpos64_t.h b/libio/bits/types/__fpos64_t.h
new file mode 100644
index 0000000000..06a6891154
--- /dev/null
+++ b/libio/bits/types/__fpos64_t.h
@@ -0,0 +1,16 @@
+#ifndef _____fpos64_t_defined
+#define _____fpos64_t_defined 1
+
+#include <bits/types.h>
+#include <bits/types/__mbstate_t.h>
+
+/* The tag name of this struct is _G_fpos64_t to preserve historic
+   C++ mangled names for functions taking fpos_t and/or fpos64_t
+   arguments.  That name should not be used in new code.  */
+typedef struct _G_fpos64_t
+{
+  __off64_t __pos;
+  __mbstate_t __state;
+} __fpos64_t;
+
+#endif
diff --git a/libio/bits/types/__fpos_t.h b/libio/bits/types/__fpos_t.h
new file mode 100644
index 0000000000..bb04576651
--- /dev/null
+++ b/libio/bits/types/__fpos_t.h
@@ -0,0 +1,16 @@
+#ifndef _____fpos_t_defined
+#define _____fpos_t_defined 1
+
+#include <bits/types.h>
+#include <bits/types/__mbstate_t.h>
+
+/* The tag name of this struct is _G_fpos_t to preserve historic
+   C++ mangled names for functions taking fpos_t arguments.
+   That name should not be used in new code.  */
+typedef struct _G_fpos_t
+{
+  __off_t __pos;
+  __mbstate_t __state;
+} __fpos_t;
+
+#endif
diff --git a/libio/bits/types/cookie_io_functions_t.h b/libio/bits/types/cookie_io_functions_t.h
new file mode 100644
index 0000000000..a6d9d39a47
--- /dev/null
+++ b/libio/bits/types/cookie_io_functions_t.h
@@ -0,0 +1,63 @@
+/* Copyright (C) 1991-2018 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef __cookie_io_functions_t_defined
+#define __cookie_io_functions_t_defined 1
+
+#include <bits/types.h>
+
+/* Functions to do I/O and file management for a stream.  */
+
+/* Read NBYTES bytes from COOKIE into a buffer pointed to by BUF.
+   Return number of bytes read.  */
+typedef __ssize_t cookie_read_function_t (void *__cookie, char *__buf,
+                                          size_t __nbytes);
+
+/* Write NBYTES bytes pointed to by BUF to COOKIE.  Write all NBYTES bytes
+   unless there is an error.  Return number of bytes written.  If
+   there is an error, return 0 and do not write anything.  If the file
+   has been opened for append (__mode.__append set), then set the file
+   pointer to the end of the file and then do the write; if not, just
+   write at the current file pointer.  */
+typedef __ssize_t cookie_write_function_t (void *__cookie, const char *__buf,
+                                           size_t __nbytes);
+
+/* Move COOKIE's file position to *POS bytes from the
+   beginning of the file (if W is SEEK_SET),
+   the current position (if W is SEEK_CUR),
+   or the end of the file (if W is SEEK_END).
+   Set *POS to the new file position.
+   Returns zero if successful, nonzero if not.  */
+typedef int cookie_seek_function_t (void *__cookie, __off64_t *__pos, int __w);
+
+/* Close COOKIE.  */
+typedef int cookie_close_function_t (void *__cookie);
+
+/* The structure with the cookie function pointers.
+   The tag name of this struct is _IO_cookie_io_functions_t to
+   preserve historic C++ mangled names for functions taking
+   cookie_io_functions_t arguments.  That name should not be used in
+   new code.  */
+typedef struct _IO_cookie_io_functions_t
+{
+  cookie_read_function_t *read;		/* Read bytes.  */
+  cookie_write_function_t *write;	/* Write bytes.  */
+  cookie_seek_function_t *seek;		/* Seek/tell file position.  */
+  cookie_close_function_t *close;	/* Close file.  */
+} cookie_io_functions_t;
+
+#endif
diff --git a/libio/bits/types/struct_FILE.h b/libio/bits/types/struct_FILE.h
new file mode 100644
index 0000000000..a120c76268
--- /dev/null
+++ b/libio/bits/types/struct_FILE.h
@@ -0,0 +1,120 @@
+/* Copyright (C) 1991-2018 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef __struct_FILE_defined
+#define __struct_FILE_defined 1
+
+/* Caution: The contents of this file are not part of the official
+   stdio.h API.  However, much of it is part of the official *binary*
+   interface, and therefore cannot be changed.  */
+
+#if defined _IO_USE_OLD_IO_FILE && !defined _LIBC
+# error "_IO_USE_OLD_IO_FILE should only be defined when building libc itself"
+#endif
+
+#if defined _IO_lock_t_defined && !defined _LIBC
+# error "_IO_lock_t_defined should only be defined when building libc itself"
+#endif
+
+#include <bits/types.h>
+
+struct _IO_FILE;
+struct _IO_marker;
+struct _IO_codecvt;
+struct _IO_wide_data;
+
+/* During the build of glibc itself, _IO_lock_t will already have been
+   defined by internal headers.  */
+#ifndef _IO_lock_t_defined
+typedef void _IO_lock_t;
+#endif
+
+/* The tag name of this struct is _IO_FILE to preserve historic
+   C++ mangled names for functions taking FILE* arguments.
+   That name should not be used in new code.  */
+struct _IO_FILE
+{
+  int _flags;		/* High-order word is _IO_MAGIC; rest is flags. */
+
+  /* The following pointers correspond to the C++ streambuf protocol. */
+  char *_IO_read_ptr;	/* Current read pointer */
+  char *_IO_read_end;	/* End of get area. */
+  char *_IO_read_base;	/* Start of putback+get area. */
+  char *_IO_write_base;	/* Start of put area. */
+  char *_IO_write_ptr;	/* Current put pointer. */
+  char *_IO_write_end;	/* End of put area. */
+  char *_IO_buf_base;	/* Start of reserve area. */
+  char *_IO_buf_end;	/* End of reserve area. */
+
+  /* The following fields are used to support backing up and undo. */
+  char *_IO_save_base; /* Pointer to start of non-current get area. */
+  char *_IO_backup_base;  /* Pointer to first valid character of backup area */
+  char *_IO_save_end; /* Pointer to end of non-current get area. */
+
+  struct _IO_marker *_markers;
+
+  struct _IO_FILE *_chain;
+
+  int _fileno;
+  int _flags2;
+  __off_t _old_offset; /* This used to be _offset but it's too small.  */
+
+  /* 1+column number of pbase(); 0 is unknown. */
+  unsigned short _cur_column;
+  signed char _vtable_offset;
+  char _shortbuf[1];
+
+  _IO_lock_t *_lock;
+#ifdef _IO_USE_OLD_IO_FILE
+};
+
+struct _IO_FILE_complete
+{
+  struct _IO_FILE _file;
+#endif
+  __off64_t _offset;
+  /* Wide character stream stuff.  */
+  struct _IO_codecvt *_codecvt;
+  struct _IO_wide_data *_wide_data;
+  struct _IO_FILE *_freeres_list;
+  void *_freeres_buf;
+  size_t __pad5;
+  int _mode;
+  /* Make sure we don't get into trouble again.  */
+  char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];
+};
+
+/* These macros are used by bits/stdio.h and internal headers.  */
+#define __getc_unlocked_body(_fp)					\
+  (__glibc_unlikely ((_fp)->_IO_read_ptr >= (_fp)->_IO_read_end)	\
+   ? __uflow (_fp) : *(unsigned char *) (_fp)->_IO_read_ptr++)
+
+#define __putc_unlocked_body(_ch, _fp)					\
+  (__glibc_unlikely ((_fp)->_IO_write_ptr >= (_fp)->_IO_write_end)	\
+   ? __overflow (_fp, (unsigned char) (_ch))				\
+   : (unsigned char) (*(_fp)->_IO_write_ptr++ = (_ch)))
+
+#define _IO_EOF_SEEN 0x10
+#define __feof_unlocked_body(_fp) (((_fp)->_flags & _IO_EOF_SEEN) != 0)
+
+#define _IO_ERR_SEEN 0x20
+#define __ferror_unlocked_body(_fp) (((_fp)->_flags & _IO_ERR_SEEN) != 0)
+
+#define _IO_USER_LOCK 0x8000
+/* Many more flag bits are defined internally.  */
+
+#endif