patch 8.1.0857: indent functionality is not separated

Problem:    Ignore functionality is not separated.
Solution:   Move indent functionality into a new file. (Yegappan Lakshmanan,
            closes #3886)
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index 3f8c8a0..52deb54 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -725,6 +725,7 @@
 	$(OUTDIR)\getchar.obj \
 	$(OUTDIR)\hardcopy.obj \
 	$(OUTDIR)\hashtab.obj \
+	$(OUTDIR)\indent.obj \
 	$(OUTDIR)\json.obj \
 	$(OUTDIR)\list.obj \
 	$(OUTDIR)\main.obj \
@@ -1414,6 +1415,8 @@
 
 $(OUTDIR)/hashtab.obj:	$(OUTDIR) hashtab.c  $(INCL)
 
+$(OUTDIR)/indent.obj:	$(OUTDIR) indent.c  $(INCL)
+
 $(OUTDIR)/gui.obj:	$(OUTDIR) gui.c  $(INCL) $(GUI_INCL)
 
 $(OUTDIR)/gui_beval.obj:	$(OUTDIR) gui_beval.c $(INCL) $(GUI_INCL)
@@ -1645,6 +1648,7 @@
 	proto/getchar.pro \
 	proto/hardcopy.pro \
 	proto/hashtab.pro \
+	proto/indent.pro \
 	proto/json.pro \
 	proto/list.pro \
 	proto/main.pro \