patch 8.2.1269: language and locale code spread out

Problem:    Language and locale code spread out.
Solution:   Move relevant code to src/locale.c. (Yegappan Lakshmanan,
            closes #6509)
diff --git a/src/Make_morph.mak b/src/Make_morph.mak
index 6fc50ed..d293829 100644
--- a/src/Make_morph.mak
+++ b/src/Make_morph.mak
@@ -70,6 +70,7 @@
 	insexpand.c						\
 	json.c							\
 	list.c							\
+	locale.c						\
 	main.c							\
 	map.c							\
 	mark.c							\