patch 8.1.1318: code for text changes is in a "misc" file

Problem:    Code for text changes is in a "misc" file.
Solution:   Move the code to change.c.
diff --git a/src/Make_sas.mak b/src/Make_sas.mak
index 0d8eb3d..7090119 100644
--- a/src/Make_sas.mak
+++ b/src/Make_sas.mak
@@ -93,6 +93,7 @@
 	autocmd.c \
 	blowfish.c \
 	buffer.c \
+	change.c \
 	charset.c \
 	crypt.c \
 	crypt_zip.c \
@@ -156,6 +157,7 @@
 	autocmd.o \
 	blowfish.o \
 	buffer.o \
+	change.o \
 	charset.o \
 	crypt.o \
 	crypt_zip.o \
@@ -219,6 +221,7 @@
 	proto/autocmd.pro \
 	proto/blowfish.pro \
 	proto/buffer.pro \
+	proto/change.pro \
 	proto/charset.pro \
 	proto/crypt.pro \
 	proto/crypt_zip.pro \
@@ -340,6 +343,8 @@
 proto/blowfish.pro:	blowfish.c
 buffer.o:		buffer.c
 proto/buffer.pro:	buffer.c
+change.o:		change.c
+proto/change.pro:	change.c
 charset.o:		charset.c
 proto/charset.pro:	charset.c
 crypt.o:		crypt.c