patch 8.1.2062: the mouse code is spread out

Problem:    The mouse code is spread out.
Solution:   Move all the mouse code to mouse.c. (Yegappan Lakshmanan,
            closes #4959)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index 281d147..bc60eb9 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -754,6 +754,7 @@
 	$(OUTDIR)/message.o \
 	$(OUTDIR)/misc1.o \
 	$(OUTDIR)/misc2.o \
+	$(OUTDIR)/mouse.o \
 	$(OUTDIR)/move.o \
 	$(OUTDIR)/mbyte.o \
 	$(OUTDIR)/normal.o \
@@ -866,7 +867,7 @@
 OBJ += $(OUTDIR)/terminal.o \
 	$(OUTDIR)/encoding.o \
 	$(OUTDIR)/keyboard.o \
-	$(OUTDIR)/mouse.o \
+	$(OUTDIR)/termmouse.o \
 	$(OUTDIR)/parser.o \
 	$(OUTDIR)/pen.o \
 	$(OUTDIR)/termscreen.o \