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 <

		   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

  ])