Provide a __has_attribute compatibility macro

__has_attribute is defined by clang and tests whether a given function
attribute is supported by clang.

Add a compatibility macro for other compilers.

Signed-off-by: Justus Winter <4winter@informatik.uni-hamburg.de>

diff --git a/compat/function-attributes.h b/compat/function-attributes.h
new file mode 100644 (file)
index 0000000..18f9090
--- /dev/null
+++ b/compat/function-attributes.h
@@ -0,0 +1,31 @@
+/* function-attributes.h - Provides compiler abstractions for
+ *                         function attributes
+ *
+ * Copyright (c) 2012 Justus Winter <4winter@informatik.uni-hamburg.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses/ .
+ */
+
+#ifndef FUNCTION_ATTRIBUTES_H
+#define FUNCTION_ATTRIBUTES_H
+
+/* clang provides this macro to test for support for function
+ * attributes. If it isn't defined, this provides a compatibility
+ * macro for other compilers.
+ */
+#ifndef __has_attribute
+#define __has_attribute(x) 0
+#endif
+
+#endif