patch 9.1.1953: gui_mch_set_titlebar_colors() is excessively called

Problem:  gui_mch_set_titlebar_colors() doesn't need to be called when
          'go+=C' is not set.
Solution: Switch the default value to false.

closes: #18872

Signed-off-by: Mao-Yining <mao.yining@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/gui.c

@@ -3494,7 +3494,7 @@ gui_init_which_components(char_u *oldval UNUSED)
     int		using_tabline;
 #endif
 #ifdef FEAT_GUI_MSWIN
-    static int	prev_titlebar = -1;
+    static int	prev_titlebar = FALSE;
     int		using_titlebar = FALSE;
 #endif
 #if defined(FEAT_MENU)

src/version.c

@@ -729,6 +729,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1953,
 /**/
     1952,
 /**/