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-rw-r--r--m4/visibility.m449
1 files changed, 37 insertions, 12 deletions
diff --git a/m4/visibility.m4 b/m4/visibility.m4
index 2ff6330aa..552e39772 100644
--- a/m4/visibility.m4
+++ b/m4/visibility.m4
@@ -1,5 +1,5 @@
-# visibility.m4 serial 1 (gettext-0.15)
-dnl Copyright (C) 2005 Free Software Foundation, Inc.
+# visibility.m4 serial 5 (gettext-0.18.2)
+dnl Copyright (C) 2005, 2008, 2010-2014 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.
@@ -12,7 +12,7 @@ dnl __attribute__((__visibility__("hidden"))) and
dnl __attribute__((__visibility__("default"))).
dnl Does *not* test for __visibility__("protected") - which has tricky
dnl semantics (see the 'vismain' test in glibc) and does not exist e.g. on
-dnl MacOS X.
+dnl Mac OS X.
dnl Does *not* test for __visibility__("internal") - which has processor
dnl dependent semantics.
dnl Does *not* test for #pragma GCC visibility push(hidden) - which is
@@ -26,18 +26,43 @@ AC_DEFUN([gl_VISIBILITY],
CFLAG_VISIBILITY=
HAVE_VISIBILITY=0
if test -n "$GCC"; then
+ dnl First, check whether -Werror can be added to the command line, or
+ dnl whether it leads to an error because of some other option that the
+ dnl user has put into $CC $CFLAGS $CPPFLAGS.
+ AC_MSG_CHECKING([whether the -Werror option is usable])
+ AC_CACHE_VAL([gl_cv_cc_vis_werror], [
+ gl_save_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS -Werror"
+ AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM([[]], [[]])],
+ [gl_cv_cc_vis_werror=yes],
+ [gl_cv_cc_vis_werror=no])
+ CFLAGS="$gl_save_CFLAGS"])
+ AC_MSG_RESULT([$gl_cv_cc_vis_werror])
+ dnl Now check whether visibility declarations are supported.
AC_MSG_CHECKING([for simple visibility declarations])
- AC_CACHE_VAL(gl_cv_cc_visibility, [
+ AC_CACHE_VAL([gl_cv_cc_visibility], [
gl_save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -fvisibility=hidden"
- AC_TRY_COMPILE(
- [extern __attribute__((__visibility__("hidden"))) int hiddenvar;
- extern __attribute__((__visibility__("default"))) int exportedvar;
- extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
- extern __attribute__((__visibility__("default"))) int exportedfunc (void);],
- [],
- gl_cv_cc_visibility=yes,
- gl_cv_cc_visibility=no)
+ dnl We use the option -Werror and a function dummyfunc, because on some
+ dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning
+ dnl "visibility attribute not supported in this configuration; ignored"
+ dnl at the first function definition in every compilation unit, and we
+ dnl don't want to use the option in this case.
+ if test $gl_cv_cc_vis_werror = yes; then
+ CFLAGS="$CFLAGS -Werror"
+ fi
+ AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[extern __attribute__((__visibility__("hidden"))) int hiddenvar;
+ extern __attribute__((__visibility__("default"))) int exportedvar;
+ extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
+ extern __attribute__((__visibility__("default"))) int exportedfunc (void);
+ void dummyfunc (void) {}
+ ]],
+ [[]])],
+ [gl_cv_cc_visibility=yes],
+ [gl_cv_cc_visibility=no])
CFLAGS="$gl_save_CFLAGS"])
AC_MSG_RESULT([$gl_cv_cc_visibility])
if test $gl_cv_cc_visibility = yes; then