patch 8.1.1785: map functionality mixed with character input

Problem:    Map functionality mixed with character input.
Solution:   Move the map functionality to a separate file. (Yegappan
            Lakshmanan, closes #4740)  Graduate the +localmap feature.
diff --git a/src/Make_morph.mak b/src/Make_morph.mak
index f292934..f75afd3 100644
--- a/src/Make_morph.mak
+++ b/src/Make_morph.mak
@@ -56,6 +56,7 @@
 	json.c							\
 	list.c							\
 	main.c							\
+	map.c							\
 	mark.c							\
 	mbyte.c							\
 	memfile.c						\