Cleaner support for usleep()

Originally committed as revision 1668 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffmpeg.c

@@ -20,6 +20,8 @@
 #include "common.h"
 #include "avformat.h"
 #include "framehook.h"
+/* usleep() */
+#include "os_support.h"
 
 #ifndef CONFIG_WIN32
 #include <unistd.h>
@@ -33,7 +35,6 @@
 #include <sys/types.h>
 #include <sys/select.h>
 #include <stdlib.h>
-#define usleep(t) _sleep2((t)/1000)
 #endif
 #include <time.h>
 #include <ctype.h>

libavformat/img.c

@@ -18,21 +18,7 @@
  */
 #include <unistd.h>
 #include "avformat.h"
-
-#ifdef __MINGW32__
-#  include <windows.h>
-#  define usleep(t)    Sleep((t) / 1000)
-#endif
-#ifdef __BEOS__
-#  ifndef usleep
-#    include <OS.h>
-#    define usleep(t)  snooze((bigtime_t)(t))
-#  endif
-#endif
-#if defined(CONFIG_OS2)
-#  include <stdlib.h>
-#  define usleep(t)    _sleep2((t) / 1000)
-#endif
+#include "../os_support.h"
 
 typedef struct {
     int width;