-#ifdef __cplusplus
-# define INLINE inline
-#elif defined(__GNUC__)
-# define INLINE __inline__
-#elif defined(_MSC_VER)
-# define INLINE __inline
-#elif defined(__ICL)
-# define INLINE __inline
-#elif defined(__INTEL_COMPILER)
-# define INLINE inline
-#elif defined(__WATCOMC__) && (__WATCOMC__ >= 1100)
-# define INLINE __inline
-#else
-# define INLINE
+#ifndef INLINE
+# ifdef __cplusplus
+# define INLINE inline
+# elif defined(__GNUC__)
+# define INLINE __inline__
+# elif defined(_MSC_VER)
+# define INLINE __inline
+# elif defined(__ICL)
+# define INLINE __inline
+# elif defined(__INTEL_COMPILER)
+# define INLINE inline
+# elif defined(__WATCOMC__) && (__WATCOMC__ >= 1100)
+# define INLINE __inline
+# elif defined(__SUNPRO_C) && defined(__C99FEATURES__)
+# define INLINE inline
+# elif (__STDC_VERSION__ >= 199901L) /* C99 */
+# define INLINE inline
+# else
+# define INLINE
+# endif
+#endif
+
+/* The __FUNCTION__ gcc variable is generally only used for debugging.
+ * If we're not using gcc, define __FUNCTION__ as a cpp symbol here.
+ */
+#ifndef __FUNCTION__
+# if (!defined(__GNUC__) || (__GNUC__ < 2))
+# if (__STDC_VERSION__ >= 199901L) /* C99 */ || \
+ (defined(__SUNPRO_C) && defined(__C99FEATURES__))
+# define __FUNCTION__ __func__
+# else
+# define __FUNCTION__ "<unknown>"
+# endif
+# endif