Imported Upstream version 1.4

[debian/gzip] / m4 / wchar.m4

diff --git a/m4/wchar.m4 b/m4/wchar.m4
index ce53a45cf5c4a8481933f2307f3e44f7a90ba0d4..b2055f925812ee9706160b3f47f9b2c54bfd42d7 100644 (file)
--- a/m4/wchar.m4
+++ b/m4/wchar.m4
@@ -1,58 +1,93 @@
 dnl A placeholder for ISO C99 <wchar.h>, for platforms that have issues.
 
-dnl Copyright (C) 2007-2009 Free Software Foundation, Inc.
+dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl Written by Eric Blake.
 
-# wchar.m4 serial 25
+# wchar.m4 serial 30
 
 AC_DEFUN([gl_WCHAR_H],
 [
   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
-  AC_CACHE_CHECK([whether <wchar.h> is standalone],
-    [gl_cv_header_wchar_h_standalone],
-    [AC_COMPILE_IFELSE([[#include <wchar.h>
-wchar_t w;]],
-      [gl_cv_header_wchar_h_standalone=yes],
-      [gl_cv_header_wchar_h_standalone=no])])
-
-  AC_REQUIRE([gt_TYPE_WINT_T])
-  if test $gt_cv_c_wint_t = yes; then
-    HAVE_WINT_T=1
-  else
-    HAVE_WINT_T=0
-  fi
-  AC_SUBST([HAVE_WINT_T])
-
-  dnl If <stddef.h> is replaced, then <wchar.h> must also be replaced.
-  AC_REQUIRE([gl_STDDEF_H])
-
-  if test $gl_cv_header_wchar_h_standalone != yes || test $gt_cv_c_wint_t != yes || test -n "$STDDEF_H"; then
-    WCHAR_H=wchar.h
-  fi
-
+  AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
   dnl Prepare for creating substitute <wchar.h>.
-  dnl Do it always: WCHAR_H may be empty here but can be set later.
   dnl Check for <wchar.h> (missing in Linux uClibc when built without wide
   dnl character support).
+  dnl <wchar.h> is always overridden, because of GNULIB_POSIXCHECK.
   AC_CHECK_HEADERS_ONCE([wchar.h])
+  gl_CHECK_NEXT_HEADERS([wchar.h])
   if test $ac_cv_header_wchar_h = yes; then
     HAVE_WCHAR_H=1
   else
     HAVE_WCHAR_H=0
   fi
   AC_SUBST([HAVE_WCHAR_H])
-  gl_CHECK_NEXT_HEADERS([wchar.h])
+
+  AC_REQUIRE([gt_TYPE_WINT_T])
+  if test $gt_cv_c_wint_t = yes; then
+    HAVE_WINT_T=1
+  else
+    HAVE_WINT_T=0
+  fi
+  AC_SUBST([HAVE_WINT_T])
+])
+
+dnl Check whether <wchar.h> is usable at all.
+AC_DEFUN([gl_WCHAR_H_INLINE_OK],
+[
+  dnl Test whether <wchar.h> suffers due to the transition from '__inline' to
+  dnl 'gnu_inline'. See <http://sourceware.org/bugzilla/show_bug.cgi?id=4022>
+  dnl and <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>. In summary,
+  dnl glibc version 2.5 or older, together with gcc version 4.3 or newer and
+  dnl the option -std=c99 or -std=gnu99, leads to a broken <wchar.h>.
+  AC_CACHE_CHECK([whether <wchar.h> uses 'inline' correctly],
+    [gl_cv_header_wchar_h_correct_inline],
+    [gl_cv_header_wchar_h_correct_inline=yes
+     AC_LANG_CONFTEST([
+       AC_LANG_SOURCE([[#define wcstod renamed_wcstod
+#include <wchar.h>
+extern int zero (void);
+int main () { return zero(); }
+]])])
+     if AC_TRY_EVAL([ac_compile]); then
+       mv conftest.$ac_objext conftest1.$ac_objext
+       AC_LANG_CONFTEST([
+         AC_LANG_SOURCE([[#define wcstod renamed_wcstod
+#include <wchar.h>
+int zero (void) { return 0; }
+]])])
+       if AC_TRY_EVAL([ac_compile]); then
+         mv conftest.$ac_objext conftest2.$ac_objext
+         if $CC -o conftest$ac_exeext $CFLAGS $LDFLAGS conftest1.$ac_objext conftest2.$ac_objext $LIBS >&AS_MESSAGE_LOG_FD 2>&1; then
+           :
+         else
+           gl_cv_header_wchar_h_correct_inline=no
+         fi
+       fi
+     fi
+     rm -f conftest1.$ac_objext conftest2.$ac_objext conftest$ac_exeext
+    ])
+  if test $gl_cv_header_wchar_h_correct_inline = no; then
+    AC_MSG_ERROR([<wchar.h> cannot be used with this compiler ($CC $CFLAGS $CPPFLAGS).
+This is a known interoperability problem of glibc <= 2.5 with gcc >= 4.3 in
+C99 mode. You have four options:
+  - Add the flag -fgnu89-inline to CC and reconfigure, or
+  - Fix your include files, using parts of
+    <http://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b037a293a48718af30d706c2e18c929d0e69a621>, or
+  - Use a gcc version older than 4.3, or
+  - Don't use the flags -std=c99 or -std=gnu99.
+Configuration aborted.])
+  fi
 ])
 
 dnl Unconditionally enables the replacement of <wchar.h>.
 AC_DEFUN([gl_REPLACE_WCHAR_H],
 [
-  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
-  WCHAR_H=wchar.h
+  dnl This is a no-op, because <wchar.h> is always overridden.
+  :
 ])
 
 AC_DEFUN([gl_WCHAR_MODULE_INDICATOR],
@@ -99,5 +134,4 @@ AC_DEFUN([gl_WCHAR_H_DEFAULTS],
   REPLACE_WCSRTOMBS=0;  AC_SUBST([REPLACE_WCSRTOMBS])
   REPLACE_WCSNRTOMBS=0; AC_SUBST([REPLACE_WCSNRTOMBS])
   REPLACE_WCWIDTH=0;    AC_SUBST([REPLACE_WCWIDTH])
-  WCHAR_H='';           AC_SUBST([WCHAR_H])
 ])