patch 8.1.2022: the option.c file is too big

Problem:    The option.c file is too big.
Solution:   Move option definitions to a separate file. (Yegappan Lakshmanan,
            closes #4918)
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index ac02e80..5c9553a 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -1604,7 +1604,7 @@
 
 $(OUTDIR)/normal.obj:	$(OUTDIR) normal.c  $(INCL)
 
-$(OUTDIR)/option.obj:	$(OUTDIR) option.c  $(INCL)
+$(OUTDIR)/option.obj:	$(OUTDIR) option.c  $(INCL) optiondefs.h
 
 $(OUTDIR)/ops.obj:	$(OUTDIR) ops.c  $(INCL)