locale: get locale_t defined

[Bruno Haible]

Hi,

According to POSIX:2008, <locale.h> should define the locale_t type. On
where the type is nowhere available, we cannot easily provide it. But
on glibc and MacOS X it is "nearly" available:
  - On glibc, it is only available with -D_GNU_SOURCE.
  - On MacOS X, it is only available with #include <xlocale.h>.

This patch provides a <locale.h> that allows you to forget about these
problems.


2009-11-22  Bruno Haible  <address@hidden>

        locale: Make locale_t available when possible.
        * lib/locale.in.h: Include <xlocale.h> when it exists.
        * m4/locale_h.m4 (gl_LOCALE_H): Check for <xlocale.h> and arrange to
        replace <locale.h> if it does not define locale_t but <xlocale.h> does.
        * modules/locale (Depends-on): Add extensions.
        (Makefile.am): Also substitute HAVE_XLOCALE_H.
        * doc/posix-headers/locale.texi: Document the problem with locale_t.

*** lib/locale.in.h.orig        2009-11-22 23:29:24.000000000 +0100
--- lib/locale.in.h     2009-11-22 22:52:59.000000000 +0100
***************
*** 29,34 ****
--- 29,39 ----
  /* NetBSD 5.0 mis-defines NULL.  */
  #include <stddef.h>
  
+ /* MacOS X 10.5 defines the locale_t type in <xlocale.h>.  */
+ #if @HAVE_XLOCALE_H@
+ # include <xlocale.h>
+ #endif
+ 
  /* The LC_MESSAGES locale category is specified in POSIX, but not in ISO C.
     On systems that don't define it, use the same value as GNU libintl.  */
  #if !defined LC_MESSAGES
*** m4/locale_h.m4.orig 2009-11-22 23:29:24.000000000 +0100
--- m4/locale_h.m4      2009-11-22 23:29:07.000000000 +0100
***************
*** 1,4 ****
! # locale_h.m4 serial 3
  dnl Copyright (C) 2007, 2009 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
--- 1,4 ----
! # locale_h.m4 serial 4
  dnl Copyright (C) 2007, 2009 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
***************
*** 6,22 ****
  
  AC_DEFUN([gl_LOCALE_H],
  [
!   AC_CACHE_CHECK([whether locale.h conforms to POSIX],
!     [gl_cv_header_working_locale_h],
!     [AC_TRY_COMPILE([#include <locale.h>
! int x = LC_MESSAGES;], [],
!        [gl_cv_header_working_locale_h=yes],
!        [gl_cv_header_working_locale_h=no])])
  
    dnl If <stddef.h> is replaced, then <locale.h> must also be replaced.
    AC_REQUIRE([gl_STDDEF_H])
  
!   if test $gl_cv_header_working_locale_h = yes && test -z "$STDDEF_H"; then
      LOCALE_H=
    else
      gl_CHECK_NEXT_HEADERS([locale.h])
--- 6,52 ----
  
  AC_DEFUN([gl_LOCALE_H],
  [
!   dnl Persuade glibc <locale.h> to define locale_t.
!   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
  
    dnl If <stddef.h> is replaced, then <locale.h> must also be replaced.
    AC_REQUIRE([gl_STDDEF_H])
  
!   AC_CACHE_CHECK([whether locale.h conforms to POSIX:2001],
!     [gl_cv_header_locale_h_posix2001],
!     [AC_TRY_COMPILE([#include <locale.h>
! int x = LC_MESSAGES;], [],
!        [gl_cv_header_locale_h_posix2001=yes],
!        [gl_cv_header_locale_h_posix2001=no])])
! 
!   dnl Check for <xlocale.h>.
!   AC_CHECK_HEADERS_ONCE([xlocale.h])
!   if test $ac_cv_header_xlocale_h = yes; then
!     HAVE_XLOCALE_H=1
!     dnl Check whether use of locale_t requires inclusion of <xlocale.h>,
!     dnl e.g. on MacOS X 10.5. If <locale.h> does not define locale_t by
!     dnl itself, we assume that <xlocale.h> will do so.
!     AC_CACHE_CHECK([whether locale.h defines locale_t],
!       [gl_cv_header_locale_has_locale_t],
!       [AC_TRY_COMPILE([#include <locale.h>
! locale_t x;], [],
!          [gl_cv_header_locale_has_locale_t=yes],
!          [gl_cv_header_locale_has_locale_t=no])
!       ])
!     if test $gl_cv_header_locale_has_locale_t = yes; then
!       gl_cv_header_locale_h_needs_xlocale_h=no
!     else
!       gl_cv_header_locale_h_needs_xlocale_h=yes
!     fi
!   else
!     HAVE_XLOCALE_H=0
!     gl_cv_header_locale_h_needs_xlocale_h=no
!   fi
!   AC_SUBST([HAVE_XLOCALE_H])
! 
!   if test -z "$STDDEF_H" \
!      && test $gl_cv_header_locale_h_posix2001 = yes \
!      && test $gl_cv_header_locale_h_needs_xlocale_h = no; then
      LOCALE_H=
    else
      gl_CHECK_NEXT_HEADERS([locale.h])
*** modules/locale.orig 2009-11-22 23:29:24.000000000 +0100
--- modules/locale      2009-11-22 22:54:24.000000000 +0100
***************
*** 7,12 ****
--- 7,13 ----
  
  Depends-on:
  include_next
+ extensions
  stddef
  
  configure.ac:
***************
*** 23,28 ****
--- 24,30 ----
          sed -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
              -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
              -e 's|@''NEXT_LOCALE_H''@|$(NEXT_LOCALE_H)|g' \
+             -e 's|@''HAVE_XLOCALE_H''@|$(HAVE_XLOCALE_H)|g' \
              < $(srcdir)/locale.in.h; \
        } > address@hidden && \
        mv address@hidden $@
*** doc/posix-headers/locale.texi.orig  2009-11-22 23:29:24.000000000 +0100
--- doc/posix-headers/locale.texi       2009-11-22 22:57:59.000000000 +0100
***************
*** 12,17 ****
--- 12,21 ----
  mingw.
  
  @item
+ The @code{locale_t} type is not defined on some platforms:
+ glibc 2.11, MacOS X 10.5.
+ 
+ @item
  Some platforms provide a @code{NULL} macro that cannot be used in arbitrary
  expressions:
  NetBSD 5.0