patch 8.1.0579: cannot attach properties to text

Problem:    Cannot attach properties to text.
Solution:   First part of adding text properties.
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index e281c89..a35708d 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -754,6 +754,7 @@
 	$(OUTDIR)\syntax.obj \
 	$(OUTDIR)\tag.obj \
 	$(OUTDIR)\term.obj \
+	$(OUTDIR)\textprop.obj \
 	$(OUTDIR)\ui.obj \
 	$(OUTDIR)\undo.obj \
 	$(OUTDIR)\userfunc.obj \
@@ -1529,6 +1530,8 @@
 
 $(OUTDIR)/term.obj:	$(OUTDIR) term.c  $(INCL)
 
+$(OUTDIR)/textprop.obj:	$(OUTDIR) textprop.c  $(INCL)
+
 $(OUTDIR)/ui.obj:	$(OUTDIR) ui.c  $(INCL)
 
 $(OUTDIR)/undo.obj:	$(OUTDIR) undo.c  $(INCL)
@@ -1667,6 +1670,7 @@
 	proto/syntax.pro \
 	proto/tag.pro \
 	proto/term.pro \
+	proto/textprop.pro \
 	proto/ui.pro \
 	proto/undo.pro \
 	proto/userfunc.pro \