various openbsd and general warning fixes - patch by Björn Sandell <biorn@dce.chalmers.se>

Originally committed as revision 6058 to svn://svn.mplayerhq.hu/mplayer/trunk/postproc

postproc/swscale.c

@@ -55,6 +55,8 @@ untested special converters
 #include <assert.h>
 #ifdef HAVE_MALLOC_H
 #include <malloc.h>
+#else
+#include <stdlib.h>
 #endif
 #include "swscale.h"
 #include "../cpudetect.h"