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_sas.mak b/src/Make_sas.mak
index c621360..e7faf56 100644
--- a/src/Make_sas.mak
+++ b/src/Make_sas.mak
@@ -113,6 +113,7 @@
 	getchar.c \
 	hardcopy.c \
 	hashtab.c \
+	indent.c \
 	json.c \
 	list.c \
 	main.c \
@@ -172,6 +173,7 @@
 	getchar.o \
 	hardcopy.o \
 	hashtab.o \
+	indent.o \
 	json.o \
 	list.o \
 	main.o \
@@ -231,6 +233,7 @@
 	proto/getchar.pro \
 	proto/hardcopy.pro \
 	proto/hashtab.pro \
+	proto/indent.pro \
 	proto/json.pro \
 	proto/list.pro \
 	proto/main.pro \
@@ -368,6 +371,8 @@
 proto/hardcopy.pro:	hardcopy.c
 hashtab.o:		hashtab.c
 proto/hashtab.pro:	hashtab.c
+indent.o:		indent.c
+proto/indent.pro:	indent.c
 json.o:			json.c
 proto/json.pro:		json.c
 list.o:			list.c