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/Makefile b/src/Makefile
index 0bfc92d..eebef25 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1629,6 +1629,7 @@
 	message.c \
 	misc1.c \
 	misc2.c \
+	mouse.c \
 	move.c \
 	mbyte.c \
 	normal.c \
@@ -1762,6 +1763,7 @@
 	objects/menu.o \
 	objects/misc1.o \
 	objects/misc2.o \
+	objects/mouse.o \
 	objects/move.o \
 	objects/mbyte.o \
 	objects/normal.o \
@@ -1921,6 +1923,7 @@
 	message.pro \
 	misc1.pro \
 	misc2.pro \
+	mouse.pro \
 	move.pro \
 	normal.pro \
 	ops.pro \
@@ -3287,6 +3290,9 @@
 objects/misc2.o: misc2.c
 	$(CCC) -o $@ misc2.c
 
+objects/mouse.o: mouse.c
+	$(CCC) -o $@ mouse.c
+
 objects/move.o: move.c
 	$(CCC) -o $@ move.c
 
@@ -3430,8 +3436,8 @@
 objects/keyboard.o: libvterm/src/keyboard.c $(TERM_DEPS)
 	$(CCCTERM) -o $@ libvterm/src/keyboard.c
 
-objects/mouse.o: libvterm/src/mouse.c $(TERM_DEPS)
-	$(CCCTERM) -o $@ libvterm/src/mouse.c
+objects/termmouse.o: libvterm/src/termmouse.c $(TERM_DEPS)
+	$(CCCTERM) -o $@ libvterm/src/termmouse.c
 
 objects/parser.o: libvterm/src/parser.c $(TERM_DEPS)
 	$(CCCTERM) -o $@ libvterm/src/parser.c
@@ -3769,6 +3775,10 @@
  auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
  proto.h globals.h
+objects/mouse.o: mouse.c vim.h protodef.h auto/config.h feature.h os_unix.h \
+ auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
+ proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
+ proto.h globals.h
 objects/move.o: move.c vim.h protodef.h auto/config.h feature.h os_unix.h \
  auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
@@ -4063,7 +4073,7 @@
 objects/keyboard.o: libvterm/src/keyboard.c libvterm/src/vterm_internal.h \
  libvterm/include/vterm.h libvterm/include/vterm_keycodes.h \
  libvterm/src/utf8.h
-objects/mouse.o: libvterm/src/mouse.c libvterm/src/vterm_internal.h \
+objects/termmouse.o: libvterm/src/termmouse.c libvterm/src/vterm_internal.h \
  libvterm/include/vterm.h libvterm/include/vterm_keycodes.h \
  libvterm/src/utf8.h
 objects/parser.o: libvterm/src/parser.c libvterm/src/vterm_internal.h \