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dnl Copyright (C) 2003, 2008 Silicon Graphics, Inc.
dnl
dnl This program is free software: you can redistribute it and/or modify it
dnl under the terms of the GNU General Public License as published by
dnl the Free Software Foundation, either version 2 of the License, or
dnl (at your option) any later version.
dnl
dnl This program is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
dnl GNU General Public License for more details.
dnl
dnl You should have received a copy of the GNU General Public License
dnl along with this program. If not, see <http://www.gnu.org/licenses/>.
AC_DEFUN([AC_FUNC_GCC_VISIBILITY],
[AC_CACHE_CHECK(whether __attribute__((visibility())) is supported,
libc_cv_visibility_attribute,
[cat > conftest.c <<EOF
int foo __attribute__ ((visibility ("hidden"))) = 1;
int bar __attribute__ ((visibility ("protected"))) = 1;
EOF
libc_cv_visibility_attribute=no
if ${CC-cc} -Werror -S conftest.c -o conftest.s \
>/dev/null 2>&1; then
if grep '\.hidden.*foo' conftest.s >/dev/null; then
if grep '\.protected.*bar' conftest.s >/dev/null; then
libc_cv_visibility_attribute=yes
fi
fi
fi
rm -f conftest.[cs]
])
if test $libc_cv_visibility_attribute = yes; then
AC_DEFINE(HAVE_VISIBILITY_ATTRIBUTE, [], [GCC supports visibility attributes])
AC_DEFINE(EXPORT, [__attribute__ ((visibility ("default"))) extern], [Visibility attribute for API symbols])
CFLAGS="${CFLAGS} -fvisibility=hidden"
else
AC_DEFINE(EXPORT, [extern], [Visibility attribute for API symbols])
fi
])
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