patch 8.1.1381: MS-Windows: missing build dependency

Problem:    MS-Windows: missing build dependency.
Solution:   Make gui_dwrite.cpp depend on gui_dwrite.h. (Ken Takata,
            closes #4423
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index 4981539..f8e406e 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -1477,7 +1477,7 @@
 
 $(OUTDIR)/gui_w32.obj:	$(OUTDIR) gui_w32.c $(INCL) $(GUI_INCL)
 
-$(OUTDIR)/gui_dwrite.obj:	$(OUTDIR) gui_dwrite.cpp $(INCL) $(GUI_INCL)
+$(OUTDIR)/gui_dwrite.obj:	$(OUTDIR) gui_dwrite.cpp gui_dwrite.h
 
 $(OUTDIR)/if_cscope.obj: $(OUTDIR) if_cscope.c  $(INCL) if_cscope.h