Cope if platform declares mbstowcs_l(), but not locale_t, in <xlocale.h>.

Previously, we included <xlocale.h> only if necessary to get the definition
of type locale_t.  According to notes in PGAC_TYPE_LOCALE_T, this is
important because on some versions of glibc that file supplies an
incompatible declaration of locale_t.  (This info may be obsolete, because
on my RHEL6 box that seems to be the *only* definition of locale_t; but
there may still be glibc's in the wild for which it's a live concern.)

It turns out though that on FreeBSD and maybe other BSDen, you can get
locale_t from stdlib.h or locale.h but mbstowcs_l() and friends only from
<xlocale.h>.  This was leaving us compiling calls to mbstowcs_l() and
friends with no visible prototype, which causes a warning and could
possibly cause actual trouble, since it's not declared to return int.

Hence, adjust the configure checks so that we'll include <xlocale.h>
either if it's necessary to get type locale_t or if it's necessary to
get a declaration of mbstowcs_l().

Report and patch by Aleksander Alekseev, somewhat whacked around by me.
Back-patch to all supported branches, since we have been using
mbstowcs_l() since 9.1.

1 files changed, 31 insertions, 1 deletions

diff --git a/config/c-library.m4 b/config/c-library.m4
index 1d28c454bae..50d068d3fb4 100644
--- a/config/c-library.m4
+++ b/config/c-library.m4
@@ -316,4 +316,34 @@ fi
 if test "$pgac_cv_type_locale_t" = 'yes (in xlocale.h)'; then
   AC_DEFINE(LOCALE_T_IN_XLOCALE, 1,
             [Define to 1 if `locale_t' requires <xlocale.h>.])
-fi])])# PGAC_HEADER_XLOCALE
+fi])# PGAC_TYPE_LOCALE_T
+
+
+# PGAC_FUNC_WCSTOMBS_L
+# --------------------
+# Try to find a declaration for wcstombs_l().  It might be in stdlib.h
+# (following the POSIX requirement for wcstombs()), or in locale.h, or in
+# xlocale.h.  If it's in the latter, define WCSTOMBS_L_IN_XLOCALE.
+#
+AC_DEFUN([PGAC_FUNC_WCSTOMBS_L],
+[AC_CACHE_CHECK([for wcstombs_l declaration], pgac_cv_func_wcstombs_l,
+[AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+[#include <stdlib.h>
+#include <locale.h>],
+[#ifndef wcstombs_l
+(void) wcstombs_l;
+#endif])],
+[pgac_cv_func_wcstombs_l='yes'],
+[AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+[#include <stdlib.h>
+#include <locale.h>
+#include <xlocale.h>],
+[#ifndef wcstombs_l
+(void) wcstombs_l;
+#endif])],
+[pgac_cv_func_wcstombs_l='yes (in xlocale.h)'],
+[pgac_cv_func_wcstombs_l='no'])])])
+if test "$pgac_cv_func_wcstombs_l" = 'yes (in xlocale.h)'; then
+  AC_DEFINE(WCSTOMBS_L_IN_XLOCALE, 1,
+            [Define to 1 if `wcstombs_l' requires <xlocale.h>.])
+fi])# PGAC_FUNC_WCSTOMBS_L