diff options
| -rw-r--r-- | lib/glm4/visibility.m4 | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/lib/glm4/visibility.m4 b/lib/glm4/visibility.m4 index 6d3f9c9..077c476 100644 --- a/lib/glm4/visibility.m4 +++ b/lib/glm4/visibility.m4 @@ -1,4 +1,4 @@ -# visibility.m4 serial 2 (gettext-0.18) +# visibility.m4 serial 3 (gettext-0.18) dnl Copyright (C) 2005, 2008-2010 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -26,15 +26,37 @@ 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="$CFLAGS -Werror" + AC_TRY_COMPILE([], [], + [gl_cv_cc_vis_werror=yes], + [gl_cv_cc_vis_werror=no]) + CFLAGS="$gl_save_CFLAGS"]) + AC_MSG_RESULT([$gl_cv_cc_vis_werror]) + dnl Now check whether visibility declarations are supported. AC_MSG_CHECKING([for simple visibility declarations]) AC_CACHE_VAL([gl_cv_cc_visibility], [ gl_save_CFLAGS="$CFLAGS" CFLAGS="$CFLAGS -fvisibility=hidden" + 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_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);], + extern __attribute__((__visibility__("default"))) int exportedfunc (void); + void dummyfunc (void) {}], [], [gl_cv_cc_visibility=yes], [gl_cv_cc_visibility=no]) |