patch 8.1.0949: MS-windows defines GUI macros different than other systems

Problem:    MS-windows defines GUI macros different than other systems.
Solution:   Swap FEAT_GUI and FEAT_GUI_MSWIN. (Hirohito Higashi, closes #3996)
diff --git a/src/version.c b/src/version.c
index 4e241ad..32abc71 100644
--- a/src/version.c
+++ b/src/version.c
@@ -780,6 +780,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    949,
+/**/
     948,
 /**/
     947,