avcodec/tableprint_vlc: Do not define functions to nothing

This avoids potential warnings
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/tableprint_vlc.h

@@ -25,14 +25,14 @@
 
 #define FFMPEG_CONFIG_H
 #define AVUTIL_LOG_H
-#define av_log(a, ...)
-#define ff_dlog(a, ...)
+#define av_log(a, ...) while(0)
+#define ff_dlog(a, ...) while(0)
 #define AVUTIL_MEM_H
 #define av_malloc(s) NULL
 #define av_malloc_array(a, b) NULL
 #define av_realloc_f(p, o, n) NULL
-#define av_free(p)
-#define av_freep(p)
+#define av_free(p) while(0)
+#define av_freep(p) while(0)
 #define AVCODEC_AVCODEC_H
 #define AVCODEC_INTERNAL_H
 #include "tableprint.h"