patch 8.2.1107: 'imactivatefunc' and 'imstatusfunc' are not used in the GUI

Problem:    'imactivatefunc' and 'imstatusfunc' are not used in the GUI.
Solution:   Adjust the #ifdefs. (closes #6367)
diff --git a/src/gui_xim.c b/src/gui_xim.c
index b5875ee..ee92301 100644
--- a/src/gui_xim.c
+++ b/src/gui_xim.c
@@ -57,7 +57,7 @@
 }
 #endif
 
-#ifdef FEAT_GUI
+#if defined(FEAT_GUI_MSWIN)
 # define USE_IMACTIVATEFUNC (!gui.in_use && *p_imaf != NUL)
 # define USE_IMSTATUSFUNC (!gui.in_use && *p_imsf != NUL)
 #else