Move the x264_mdate() declaration to the appropriate header

common/common.h

@@ -257,9 +257,6 @@ void  x264_free( void * );
 /* x264_slurp_file: malloc space for the whole file and read it */
 char *x264_slurp_file( const char *filename );
 
-/* mdate: return the current date in microsecond */
-int64_t x264_mdate( void );
-
 /* x264_param2string: return a (malloced) string containing most of
  * the encoding options */
 char *x264_param2string( x264_param_t *p, int b_res );

common/osdep.h

@@ -92,6 +92,9 @@ int x264_stat( const char *path, x264_struct_stat *buf );
 #define x264_stat        stat
 #endif
 
+/* mdate: return the current date in microsecond */
+int64_t x264_mdate( void );
+
 #if defined(_WIN32) && !HAVE_WINRT
 int x264_vfprintf( FILE *stream, const char *format, va_list arg );
 int x264_is_pipe( const char *path );