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# visibility.m4 serial 4 (gettext-0.18.2)
dnl Copyright (C) 2005, 2008, 2010-2011 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 From Bruno Haible.
dnl Tests whether the compiler supports the command-line option
dnl -fvisibility=hidden and the function and variable attributes
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 Does *not* test for __visibility__("internal") - which has processor
dnl dependent semantics.
dnl Does *not* test for #pragma GCC visibility push(hidden) - which is
dnl "really only recommended for legacy code".
dnl Set the variable CFLAG_VISIBILITY.
dnl Defines and sets the variable HAVE_VISIBILITY.
dnl Modified to fit with PCRE build environment by Cristian Rodríguez.
AC_DEFUN([PCRE_VISIBILITY],
[
AC_REQUIRE([AC_PROG_CC])
VISIBILITY_CFLAGS=
VISIBILITY_CXXFLAGS=
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 $CPPFLAGS.
AC_MSG_CHECKING([whether the -Werror option is usable])
AC_CACHE_VAL([pcre_cv_cc_vis_werror], [
pcre_save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -Werror"
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([[]], [[]])],
[pcre_cv_cc_vis_werror=yes],
[pcre_cv_cc_vis_werror=no])
CFLAGS="$pcre_save_CFLAGS"])
AC_MSG_RESULT([$pcre_cv_cc_vis_werror])
dnl Now check whether visibility declarations are supported.
AC_MSG_CHECKING([for simple visibility declarations])
AC_CACHE_VAL([pcre_cv_cc_visibility], [
pcre_save_CFLAGS="$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 $pcre_cv_cc_vis_werror = yes; then
CFLAGS="$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) {}
]],
[[]])],
[pcre_cv_cc_visibility=yes],
[pcre_cv_cc_visibility=no])
CFLAGS="$pcre_save_CFLAGS"])
AC_MSG_RESULT([$pcre_cv_cc_visibility])
if test $pcre_cv_cc_visibility = yes; then
VISIBILITY_CFLAGS="-fvisibility=hidden"
VISIBILITY_CXXFLAGS="-fvisibility=hidden -fvisibility-inlines-hidden"
HAVE_VISIBILITY=1
AC_DEFINE(PCRE_EXP_DECL, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
AC_DEFINE(PCRE_EXP_DEFN, [__attribute__ ((visibility ("default")))], [to make a symbol visible])
AC_DEFINE(PCRE_EXP_DATA_DEFN, [__attribute__ ((visibility ("default")))], [to make a symbol visible])
AC_DEFINE(PCREPOSIX_EXP_DECL, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
AC_DEFINE(PCREPOSIX_EXP_DEFN, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
AC_DEFINE(PCRECPP_EXP_DECL, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
AC_DEFINE(PCRECPP_EXP_DEFN, [__attribute__ ((visibility ("default")))], [to make a symbol visible])
fi
fi
AC_SUBST([VISIBILITY_CFLAGS])
AC_SUBST([VISIBILITY_CXXFLAGS])
AC_SUBST([HAVE_VISIBILITY])
AC_DEFINE_UNQUOTED([HAVE_VISIBILITY], [$HAVE_VISIBILITY],
[Define to 1 if the compiler supports simple visibility declarations.])
])
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