patch 8.2.0443: clipboard code is spread out

Problem:    Clipboard code is spread out.
Solution:   Move clipboard code to its own file. (Yegappan Lakshmanan,
            closes #5827)
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index a6825d5..86c319f 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -730,6 +730,7 @@
 	$(OUTDIR)\change.obj \
 	$(OUTDIR)\charset.obj \
 	$(OUTDIR)\cindent.obj \
+	$(OUTDIR)\clipboard.obj \
 	$(OUTDIR)\cmdexpand.obj \
 	$(OUTDIR)\cmdhist.obj \
 	$(OUTDIR)\crypt.obj \
@@ -1515,6 +1516,8 @@
 
 $(OUTDIR)/cindent.obj:	$(OUTDIR) cindent.c  $(INCL)
 
+$(OUTDIR)/clipboard.obj:	$(OUTDIR) clipboard.c  $(INCL)
+
 $(OUTDIR)/cmdexpand.obj:	$(OUTDIR) cmdexpand.c  $(INCL)
 
 $(OUTDIR)/cmdhist.obj:	$(OUTDIR) cmdhist.c  $(INCL)
@@ -1862,6 +1865,7 @@
 	proto/change.pro \
 	proto/charset.pro \
 	proto/cindent.pro \
+	proto/clipboard.pro \
 	proto/cmdexpand.pro \
 	proto/cmdhist.pro \
 	proto/crypt.pro \