Check for __attribute__((visibility("hidden"))).

diff --git a/configure.ac b/configure.ac
index 08c64a5..fb68d16 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -30,6 +30,32 @@ AC_CANONICAL_TARGET
 AM_INIT_AUTOMAKE
 AM_CONFIG_HEADER([config.h])
 
+dnl Check for __attribute__((visibility()))
+AC_CACHE_CHECK([whether __attribute__((visibility())) is supported],
+  vaapi_cv_visibility_attribute,
+  [cat > conftest.c <<EOF
+int foo __attribute__ ((visibility ("hidden"))) = 1;
+int bar __attribute__ ((visibility ("protected"))) = 1;
+EOF
+  vaapi_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
+       vaapi_cv_visibility_attribute=yes
+      fi
+    fi
+  fi
+  rm -f conftest.[cs]
+])
+if test $vaapi_cv_visibility_attribute = yes; then
+  vaapi_cv_visibility_attribute_hidden="__attribute__((visibility(\"hidden\")))"
+else
+  vaapi_cv_visibility_attribute_hidden=""
+fi
+AC_DEFINE_UNQUOTED([attribute_hidden],
+                   [$vaapi_cv_visibility_attribute_hidden],
+                   [Define the "hidden" visibility attribute])
+
 dnl Versions for GStreamer and plugins-base
 GST_MAJORMINOR=gst_major_minor_version
 GST_VERSION_REQUIRED=gst_version