Add configure check for nonnull attribute

The main reason I do this is to document the minimum compiler version
(GCC 3.3) for the attribute. But it may work with other compilers, too.

Signed-off-by: Kang-Che Sung <explorer09@gmail.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/Macros.h b/Macros.h
index 054e7d3b..db411e93 100644
--- a/Macros.h
+++ b/Macros.h
@@ -42,7 +42,6 @@ in the source distribution for its full text.
 #ifdef  __GNUC__  // defined by GCC and Clang
 
 #define ATTR_FORMAT(type, index, check) __attribute__((format (type, index, check)))
-#define ATTR_NONNULL                    __attribute__((nonnull))
 #define ATTR_NORETURN                   __attribute__((noreturn))
 #define ATTR_UNUSED                     __attribute__((unused))
 #define ATTR_MALLOC                     __attribute__((malloc))
@@ -50,13 +49,24 @@ in the source distribution for its full text.
 #else /* __GNUC__ */
 
 #define ATTR_FORMAT(type, index, check)
-#define ATTR_NONNULL
 #define ATTR_NORETURN
 #define ATTR_UNUSED
 #define ATTR_MALLOC
 
 #endif /* __GNUC__ */
 
+#ifdef HAVE_ATTR_NONNULL
+
+#define ATTR_NONNULL                    __attribute__((nonnull))
+#define ATTR_NONNULL_N(...)             __attribute__((nonnull(__VA_ARGS__)))
+
+#else
+
+#define ATTR_NONNULL
+#define ATTR_NONNULL_N(...)
+
+#endif /* HAVE_ATTR_NONNULL */
+
 #ifdef HAVE_ATTR_ALLOC_SIZE
 
 #define ATTR_ALLOC_SIZE1(a)             __attribute__((alloc_size (a)))