Add some #includes to allow compilation without HAVE_AV_CONFIG_H.

taken from a patch by Ronald S. Bultje, rbultje ronald.bitfreak net


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@9263 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/dct-test.c

@@ -30,6 +30,7 @@
 #include <string.h>
 #include <sys/time.h>
 #include <unistd.h>
+#include <math.h>
 
 #include "dsputil.h"
 

libavcodec/fft-test.c

@@ -27,6 +27,8 @@
 #include <math.h>
 #include <unistd.h>
 #include <sys/time.h>
+#include <stdlib.h>
+#include <string.h>
 
 #undef exit