patch 8.1.2077: the ops.c file is too big

Problem:    The ops.c file is too big.
Solution:   Move code for dealing with registers to a new file. (Yegappan
            Lakshmanan, closes #4982)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index bc60eb9..3bc57aa 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -769,6 +769,7 @@
 	$(OUTDIR)/profiler.o \
 	$(OUTDIR)/quickfix.o \
 	$(OUTDIR)/regexp.o \
+	$(OUTDIR)/register.o \
 	$(OUTDIR)/scriptfile.o \
 	$(OUTDIR)/screen.o \
 	$(OUTDIR)/search.o \
@@ -1186,6 +1187,9 @@
 $(OUTDIR)/regexp.o:	regexp.c regexp_bt.c regexp_nfa.c $(INCL)
 	$(CC) -c $(CFLAGS) regexp.c -o $@
 
+$(OUTDIR)/register.o:	register.c $(INCL)
+	$(CC) -c $(CFLAGS) register.c -o $@
+
 $(OUTDIR)/terminal.o:	terminal.c $(INCL) $(TERM_DEPS)
 	$(CC) -c $(CFLAGS) terminal.c -o $@