patch 8.2.0516: client-server code is spread out

Problem:    Client-server code is spread out.
Solution:   Move client-server code to a new file. (Yegappan Lakshmanan,
            closes #5885)
diff --git a/src/Make_morph.mak b/src/Make_morph.mak
index 7273182..1830d85 100644
--- a/src/Make_morph.mak
+++ b/src/Make_morph.mak
@@ -33,6 +33,7 @@
 	change.c						\
 	charset.c						\
 	cindent.c						\
+	clientserver.c						\
 	clipboard.c						\
 	cmdexpand.c						\
 	cmdhist.c						\