patch 8.2.0256: time and timer related code is spread out

Problem:    Time and timer related code is spread out.
Solution:   Move time and timer related code to a new file. (Yegappan
            Lakshmanan, closes #5604)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index 639f3e5..99c004f 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -783,6 +783,7 @@
 	$(OUTDIR)/term.o \
 	$(OUTDIR)/testing.o \
 	$(OUTDIR)/textprop.o \
+	$(OUTDIR)/time.o \
 	$(OUTDIR)/ui.o \
 	$(OUTDIR)/undo.o \
 	$(OUTDIR)/usercmd.o \