Only define gcc function attributes on gcc.

These gcc extensions help the compiler optimize function calls,
but are unavailable if dss is not compiled with gcc.

This patch defines the corresponding macros to empty if __GNUC__
is not defined, or if the gcc version is too old to support the
particular function attribute.

diff --git a/gcc-compat.h b/gcc-compat.h
index 4451980678907b4e2dcb76b9cda8c0e365d2a6f7..a15b0cef5c0f4b10672ab8a620429438baa1e1c2 100644 (file)
--- a/gcc-compat.h
+++ b/gcc-compat.h
@@ -1,11 +1,35 @@
+#define HAVE_GNUC(maj, min) \
+       defined(__GNUC__) && \
+       (__GNUC__ > maj || (__GNUC__ == maj && __GNUC_MINOR__ >= min))
+
+#if HAVE_GNUC(2,5)
 # define __noreturn    __attribute__ ((noreturn))
+#else
+# define __noreturn
+#endif
+
+#if HAVE_GNUC(3,0)
 # define __malloc      __attribute__ ((malloc))
+#else
+# define __malloc
+#endif
+
+#if HAVE_GNUC(2,7)
 # define __a_unused    __attribute__ ((unused))
+#else
+# define __a_unused
+#endif
+
 /* 
  * p is the number of the "format string" parameter, and q is 
  * the number of the first variadic parameter 
  */
+#if HAVE_GNUC(2,3)
 # define __printf(p,q) __attribute__ ((format (printf, p, q)))
+#else
+# define __printf(p,q)
+#endif
+
 /*
  * as direct use of __printf(p,q) confuses doxygen, here are two extra macros
  * for those values p,q that are actually used by paraslash.
@@ -13,10 +37,10 @@
 #define  __printf_1_2 __printf(1,2)
 #define  __printf_2_3 __printf(2,3)
 
-# if __GNUC__ > 3  || (__GNUC__ == 3 && __GNUC_MINOR__ > 3)
+#if HAVE_GNUC(3,3)
 # define __must_check  __attribute__ ((warn_unused_result))
-# else
+#else
 # define __must_check  /* no warn_unused_result */
-# endif
+#endif
 
 #define _static_inline_ static inline