patch 8.2.0838: MS-Windows: compiler warning for uninitialized variables

Problem:    MS-Windows: compiler warning for uninitialized variables.
Solution:   Initialize variables.
diff --git a/src/screen.c b/src/screen.c
index e218196..6893ca3 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -1882,7 +1882,7 @@
 {
     int	    do_ME = FALSE;	    // output T_ME code
 #if defined(FEAT_VTP) && defined(FEAT_TERMGUICOLORS)
-    int	    do_ME_fg, do_ME_bg;
+    int	    do_ME_fg = FALSE, do_ME_bg = FALSE;
 #endif
 
     if (screen_attr != 0