patch 8.1.2127: the indent.c file is a bit big

Problem:    The indent.c file is a bit big.
Solution:   Move C-indent code a a new cindent.c file.  Move other
            indent-related code to indent.c. (Yegappan Lakshmanan,
            closes #5031)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index 503761c..f04d11b 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -712,6 +712,7 @@
 	$(OUTDIR)/bufwrite.o \
 	$(OUTDIR)/change.o \
 	$(OUTDIR)/charset.o \
+	$(OUTDIR)/cindent.o \
 	$(OUTDIR)/cmdexpand.o \
 	$(OUTDIR)/cmdhist.o \
 	$(OUTDIR)/crypt.o \