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_dice.mak b/src/Make_dice.mak
index 83614ca..57aed47 100644
--- a/src/Make_dice.mak
+++ b/src/Make_dice.mak
@@ -50,6 +50,7 @@
 	getchar.c \
 	hardcopy.c \
 	hashtab.c \
+	indent.c \
 	json.c \
 	list.c \
 	main.c \
@@ -108,6 +109,7 @@
 	o/getchar.o \
 	o/hardcopy.o \
 	o/hashtab.o \
+	o/indent.o \
 	o/json.o \
 	o/list.o \
 	o/main.o \
@@ -209,6 +211,8 @@
 
 o/hashtab.o: hashtab.c	$(SYMS)
 
+o/indent.o:	indent.c  $(SYMS)
+
 o/json.o:	json.c  $(SYMS)
 
 o/list.o:	list.c  $(SYMS)