add some gcc hint defines

The defines can help the compiler to produce better warnings
and errors.

This is manual cherrypicked from nmh

diff --git a/h/mh.h b/h/mh.h
index 649582d..88bcde5 100644 (file)
--- a/h/mh.h
+++ b/h/mh.h
@@ -38,8 +38,26 @@ typedef unsigned char  boolean;  /* not int so we can pack in a structure */
 */
 #if __GNUC__ > 2
 # define NORETURN __attribute__((__noreturn__))
+# define CONST __attribute__((const))
+# define MALLOC __attribute__((malloc))
+# define NONNULL(...) __attribute__((nonnull(__VA_ARGS__)))
+# define PURE __attribute__((pure))
+# define ENDNULL __attribute__((sentinel))
 #else
 # define NORETURN
+# define CONST
+# define MALLOC
+# define NONNULL(...)
+# define PURE
+# define ENDNULL
+#endif
+
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
+# define ALLOC_SIZE(...) __attribute__((alloc_size(__VA_ARGS__)))
+# define CHECK_PRINTF(fmt, arg) __attribute__((format(printf, fmt, arg)))
+#else
+# define ALLOC_SIZE(...)
+# define CHECK_PRINTF(fmt, arg)
 #endif
 
 /*