patch 8.2.0872: XIM code is mixed with multi-byte code

Problem:    XIM code is mixed with multi-byte code.
Solution:   Move the XIM code to a separate file. (Yegappan Lakshmanan,
            closes #6177)
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index aec94a9..8559c9d 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -761,6 +761,7 @@
 	$(OUTDIR)\findfile.obj \
 	$(OUTDIR)\fold.obj \
 	$(OUTDIR)\getchar.obj \
+	$(OUTDIR)\gui_xim.obj \
 	$(OUTDIR)\hardcopy.obj \
 	$(OUTDIR)\hashtab.obj \
 	$(OUTDIR)\highlight.obj \
@@ -1591,6 +1592,8 @@
 
 $(OUTDIR)/getchar.obj:	$(OUTDIR) getchar.c  $(INCL)
 
+$(OUTDIR)/gui_xim.obj:	$(OUTDIR) gui_xim.c  $(INCL)
+
 $(OUTDIR)/hardcopy.obj:	$(OUTDIR) hardcopy.c  $(INCL) version.h
 
 $(OUTDIR)/hashtab.obj:	$(OUTDIR) hashtab.c  $(INCL)
@@ -1908,6 +1911,7 @@
 	proto/filepath.pro \
 	proto/findfile.pro \
 	proto/getchar.pro \
+	proto/gui_xim.pro \
 	proto/hardcopy.pro \
 	proto/hashtab.pro \
 	proto/highlight.pro \