move NULL_IF_CONFIG_SMALL() definition into internal header

Originally committed as revision 16619 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/common.h

@@ -323,15 +323,4 @@ static inline av_pure int ff_get_fourcc(const char *s){
         }\
     }
 
-/**
- * Returns NULL if CONFIG_SMALL is true otherwise the argument
- * without modifications, used to disable the definition of strings
- * (for example AVCodec long_names).
- */
-#if CONFIG_SMALL
-#   define NULL_IF_CONFIG_SMALL(x) NULL
-#else
-#   define NULL_IF_CONFIG_SMALL(x) x
-#endif
-
 #endif /* AVUTIL_COMMON_H */

libavutil/internal.h

@@ -302,4 +302,15 @@ static av_always_inline av_const float truncf(float x)
 }
 #endif /* HAVE_TRUNCF */
 
+/**
+ * Returns NULL if CONFIG_SMALL is true otherwise the argument
+ * without modifications, used to disable the definition of strings
+ * (for example AVCodec long_names).
+ */
+#if CONFIG_SMALL
+#   define NULL_IF_CONFIG_SMALL(x) NULL
+#else
+#   define NULL_IF_CONFIG_SMALL(x) x
+#endif
+
 #endif /* AVUTIL_INTERNAL_H */