Rename xlocale.h to bits/types/__locale_t.h.

xlocale.h is already a single-type micro-header, defining struct
__locale_struct and the typedefs __locale_t and locale_t.  This patch
brings it into the bits/types/ scheme: there are now
bits/types/__locale_t.h which defines only __locale_struct and
__locale_t, and bits/types/locale_t.h which defines locale_t as well
as the other two.  None of *our* headers need __locale_t.h, but it
appears to me that libstdc++ could make use of it.

There are a lot of external uses of xlocale.h, but all the uses I
checked had an autoconf test or equivalent for its existence.  It has
never been available from other C libraries, and it has always
contained a comment reading "This file is not standardized, don't rely
on it, it can go away without warning" so I think dropping it is
pretty safe.

I also took the opportunity to clean up comments in various public
header files that still talk about the *_l interfaces as though they
were completely nonstandard.  There are a few of them, notably the
strtoX_l and wcstoX_l families, that haven't been standardized, but
the bulk are in POSIX.1-2008.

        * locale/xlocale.h: Rename to...
	* locale/bits/types/__locale_t.h: ...here.  Adjust commentary.
	Only define struct __locale_struct and __locale_t, not locale_t.
        * locale/bits/types/locale_t.h: New file; define locale_t here.
        * locale/Makefile (headers): Update to match.

        * include/xlocale.h: Delete wrapper.
        * include/bits/types/__locale_t.h: New wrapper.
        * include/bits/types/locale_t.h: New wrapper.

        * ctype/ctype.h, include/printf.h, include/time.h
        * locale/langinfo.h, locale/locale.h, stdlib/monetary.h
        * stdlib/stdlib.h, string/string.h, string/strings.h, time/time.h
        * wcsmbs/wchar.h, wctype/wctype.h: Use bits/types/locale_t.h.
        Correct outdated comments regarding the standardization status of
        the functions that take locale_t arguments.

        * stdlib/strtod_l.c, stdlib/strtof_l.c, stdlib/strtol_l.c
        * stdlib/strtold_l.c, stdlib/strtoul_l.c, stdlib/strtoull_l.c
        * sysdeps/ieee754/ldbl-128ibm/strtold_l.c
        * sysdeps/ieee754/ldbl-64-128/strtold_l.c
        * wcsmbs/wcstod.c, wcsmbs/wcstod_l.c, wcsmbs/wcstof.c
        * wcsmbs/wcstof_l.c, wcsmbs/wcstold.c, wcsmbs/wcstold_l.c:
        Don't include xlocale.h. If necessary, include locale.h instead.

        * stdlib/strtold_l.c: Unconditionally include wchar.h.

5 files changed, 49 insertions, 31 deletions

diff --git a/locale/Makefile b/locale/Makefile
index d9ef48fe93..98ee76272d 100644
--- a/locale/Makefile
+++ b/locale/Makefile
@@ -22,7 +22,8 @@ subdir	:= locale
 
 include ../Makeconfig
 
-headers		= locale.h bits/locale.h langinfo.h xlocale.h
+headers		= langinfo.h locale.h bits/locale.h \
+		  bits/types/locale_t.h bits/types/__locale_t.h
 routines	= setlocale findlocale loadlocale loadarchive \
 		  localeconv nl_langinfo nl_langinfo_l mb_cur_max \
 		  newlocale duplocale freelocale uselocale
diff --git a/locale/xlocale.h b/locale/bits/types/__locale_t.h
index 20b2c1109f..4511aa1929 100644
--- a/locale/xlocale.h
+++ b/locale/bits/types/__locale_t.h
@@ -1,4 +1,4 @@
-/* Definition of locale datatype.
+/* Definition of struct __locale_struct and __locale_t.
    Copyright (C) 1997-2017 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
@@ -17,14 +17,15 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#ifndef _XLOCALE_H
-#define _XLOCALE_H	1
+#ifndef _BITS_TYPES___LOCALE_T_H
+#define _BITS_TYPES___LOCALE_T_H 1
 
-/* Structure for reentrant locale using functions.  This is an
-   (almost) opaque type for the user level programs.  The file and
-   this data structure is not standardized.  Don't rely on it.  It can
-   go away without warning.  */
-typedef struct __locale_struct
+/* POSIX.1-2008: the locale_t type, representing a locale context
+   (implementation-namespace version).  This type should be treated
+   as opaque by applications; some details are exposed for the sake of
+   efficiency in e.g. ctype functions.  */
+
+struct __locale_struct
 {
   /* Note: LC_ALL is not a valid index into this array.  */
   struct __locale_data *__locales[13]; /* 13 = __LC_LAST. */
@@ -36,9 +37,8 @@ typedef struct __locale_struct
 
   /* Note: LC_ALL is not a valid index into this array.  */
   const char *__names[13];
-} *__locale_t;
+};
 
-/* POSIX 2008 makes locale_t official.  */
-typedef __locale_t locale_t;
+typedef struct __locale_struct *__locale_t;
 
-#endif /* xlocale.h */
+#endif /* bits/types/__locale_t.h */
diff --git a/locale/bits/types/locale_t.h b/locale/bits/types/locale_t.h
new file mode 100644
index 0000000000..de7ec2ee84
--- /dev/null
+++ b/locale/bits/types/locale_t.h
@@ -0,0 +1,26 @@
+/* Definition of locale_t.
+   Copyright (C) 2017 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 _BITS_TYPES_LOCALE_T_H
+#define _BITS_TYPES_LOCALE_T_H 1
+
+#include <bits/types/__locale_t.h>
+
+typedef __locale_t locale_t;
+
+#endif /* bits/types/locale_t.h */
diff --git a/locale/langinfo.h b/locale/langinfo.h
index 759adfbd1f..93d84463b5 100644
--- a/locale/langinfo.h
+++ b/locale/langinfo.h
@@ -584,11 +584,8 @@ extern char *nl_langinfo (nl_item __item) __THROW;
 
 
 #ifdef __USE_XOPEN2K8
-/* This interface is for the extended locale model.  See <locale.h> for
-   more information.  */
-
-/* Get locale datatype definition.  */
-# include <xlocale.h>
+/* POSIX.1-2008 extended locale interface (see locale.h).  */
+# include <bits/types/locale_t.h>
 
 /* Just like nl_langinfo but get the information from the locale object L.  */
 extern char *nl_langinfo_l (nl_item __item, __locale_t __l);
diff --git a/locale/locale.h b/locale/locale.h
index 9a5fce9d47..6c1b22051b 100644
--- a/locale/locale.h
+++ b/locale/locale.h
@@ -126,19 +126,13 @@ extern struct lconv *localeconv (void) __THROW;
 
 
 #ifdef	__USE_XOPEN2K8
-/* The concept of one static locale per category is not very well
-   thought out.  Many applications will need to process its data using
-   information from several different locales.  Another application is
-   the implementation of the internationalization handling in the
-   upcoming ISO C++ standard library.  To support this another set of
-   the functions using locale data exist which have an additional
-   argument.
-
-   Attention: all these functions are *not* standardized in any form.
-   This is a proof-of-concept implementation.  */
-
-/* Get locale datatype definition.  */
-# include <xlocale.h>
+/* POSIX.1-2008 extends the locale interface with functions for
+   explicit creation and manipulation of 'locale_t' objects
+   representing locale contexts, and a set of parallel
+   locale-sensitive text processing functions that take a locale_t
+   argument.  This enables applications to work with data from
+   multiple locales simultaneously and thread-safely.  */
+# include <bits/types/locale_t.h>
 
 /* Return a reference to a data structure representing a set of locale
    datasets.  Unlike for the CATEGORY parameter for `setlocale' the