Fix the self tests which are contained in some codecs and are using random().

Originally committed as revision 9755 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/ac3enc.c

@@ -1269,6 +1269,7 @@ static int AC3_encode_close(AVCodecContext *avctx)
 /*************************************************************************/
 /* TEST */
 
+#undef random
 #define FN (N/4)
 
 void fft_test(void)

libavcodec/cabac.c

@@ -179,6 +179,7 @@ void ff_init_cabac_states(CABACContext *c){
 }
 
 #if 0 //selftest
+#undef random
 #define SIZE 10240
 
 #include "avcodec.h"

libavcodec/h264.c

@@ -8101,6 +8101,7 @@ static inline void fill_mb_avail(H264Context *h){
 #endif
 
 #if 0 //selftest
+#undef random
 #define COUNT 8000
 #define SIZE (COUNT*40)
 int main(){

libavcodec/snow.c

@@ -4552,6 +4552,7 @@ AVCodec snow_encoder = {
 #undef malloc
 #undef free
 #undef printf
+#undef random
 
 int main(){
     int width=256;