| 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]) |
| fi |
| ]) |
