Add libavutil/mathematics.h #includes for INFINITY

This fixes build errors in some environments.
Signed-off-by: Mans Rullgard <mans@mansr.com>

cmdutils.c

@@ -35,6 +35,7 @@
 #include "libswscale/swscale.h"
 #include "libpostproc/postprocess.h"
 #include "libavutil/avstring.h"
+#include "libavutil/mathematics.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/eval.h"

libavcodec/aaccoder.c

@@ -33,6 +33,7 @@
 #include "libavutil/libm.h" // brought forward to work around cygwin header breakage
 
 #include <float.h>
+#include "libavutil/mathematics.h"
 #include "avcodec.h"
 #include "put_bits.h"
 #include "aac.h"

libavcodec/nellymoserenc.c

@@ -35,6 +35,7 @@
  * http://wiki.multimedia.cx/index.php?title=Nellymoser
  */
 
+#include "libavutil/mathematics.h"
 #include "nellymoser.h"
 #include "avcodec.h"
 #include "dsputil.h"