include all prerequisites in header files

Originally committed as revision 9344 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/simple_idct.h

@@ -25,6 +25,9 @@
  * simple idct header.
  */
 
+#include <stdint.h>
+#include "dsputil.h"
+
 void simple_idct_put(uint8_t *dest, int line_size, DCTELEM *block);
 void simple_idct_add(uint8_t *dest, int line_size, DCTELEM *block);
 void ff_simple_idct_mmx(int16_t *block);