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_bc5.mak b/src/Make_bc5.mak
index d0d31d4..b2977e7 100644
--- a/src/Make_bc5.mak
+++ b/src/Make_bc5.mak
@@ -548,6 +548,7 @@
 	$(OBJDIR)\getchar.obj \
 	$(OBJDIR)\hardcopy.obj \
 	$(OBJDIR)\hashtab.obj \
+	$(OBJDIR)\indent.obj \
 	$(OBJDIR)\json.obj \
 	$(OBJDIR)\list.obj \
 	$(OBJDIR)\main.obj \