1 files changed, 46 insertions, 0 deletions
diff --git a/libgfortran/acinclude.m4 b/libgfortran/acinclude.m4
index 87dc72283f9..2dc8f85e16b 100644
--- a/libgfortran/acinclude.m4
+++ b/libgfortran/acinclude.m4
@@ -102,3 +102,49 @@ else
       [Define to 1 if the target is ILP32.])
   fi
   ])
+
+dnl Check whether the target supports hidden visibility.
+AC_DEFUN([LIBGFOR_CHECK_ATTRIBUTE_VISIBILITY], [
+  AC_CACHE_CHECK([whether the target supports hidden visibility],
+		 have_attribute_visibility, [
+  save_CFLAGS="$CFLAGS"
+  CFLAGS="$CFLAGS -Werror"
+  AC_TRY_COMPILE([void __attribute__((visibility("hidden"))) foo(void) { }],
+		 [], have_attribute_visibility=yes,
+		 have_attribute_visibility=no)
+  CFLAGS="$save_CFLAGS"])
+  if test $have_attribute_visibility = yes; then
+    AC_DEFINE(HAVE_ATTRIBUTE_VISIBILITY, 1,
+      [Define to 1 if the target supports __attribute__((visibility(...))).])
+  fi])
+
+dnl Check whether the target supports dllexport
+AC_DEFUN([LIBGFOR_CHECK_ATTRIBUTE_DLLEXPORT], [
+  AC_CACHE_CHECK([whether the target supports dllexport],
+		 have_attribute_dllexport, [
+  save_CFLAGS="$CFLAGS"
+  CFLAGS="$CFLAGS -Werror"
+  AC_TRY_COMPILE([void __attribute__((dllexport)) foo(void) { }],
+		 [], have_attribute_dllexport=yes,
+		 have_attribute_dllexport=no)
+  CFLAGS="$save_CFLAGS"])
+  if test $have_attribute_dllexport = yes; then
+    AC_DEFINE(HAVE_ATTRIBUTE_DLLEXPORT, 1,
+      [Define to 1 if the target supports __attribute__((dllexport)).])
+  fi])
+
+dnl Check whether the target supports symbol aliases.
+AC_DEFUN([LIBGFOR_CHECK_ATTRIBUTE_ALIAS], [
+  AC_CACHE_CHECK([whether the target supports symbol aliases],
+		 have_attribute_alias, [
+  AC_TRY_LINK([
+#define ULP	STR1(__USER_LABEL_PREFIX__)
+#define STR1(x)	STR2(x)
+#define STR2(x)	#x
+void foo(void) { }
+extern void bar(void) __attribute__((alias(ULP "foo")));],
+    [bar();], have_attribute_alias=yes, have_attribute_alias=no)])
+  if test $have_attribute_alias = yes; then
+    AC_DEFINE(HAVE_ATTRIBUTE_ALIAS, 1,
+      [Define to 1 if the target supports __attribute__((alias(...))).])
+  fi])