(svn r26360) -Revert (r25550) / Fix [FS#5922]: ClientSizeChanged is only called via WndProcGdi which already has the mutex. The issue which r25550 tried to fix still exists as FS#5867.

src/video/win32_v.cpp

@@ -184,7 +184,6 @@ static void ClientSizeChanged(int w, int h)
 {
 	/* allocate new dib section of the new size */
 	if (AllocateDibSection(w, h)) {
-		if (_draw_mutex != NULL) _draw_mutex->BeginCritical();
 		/* mark all palette colours dirty */
 		_cur_palette.first_dirty = 0;
 		_cur_palette.count_dirty = 256;
@@ -199,8 +198,6 @@ static void ClientSizeChanged(int w, int h)
 			_screen.dst_ptr = _wnd.buffer_bits;
 			UpdateWindows();
 		}
-
-		if (_draw_mutex != NULL) _draw_mutex->EndCritical();
 	}
 }