patch 8.1.0480: MinGW build file uses different -I flags than MVC

Problem:    MinGW build file uses different -I flags than MVC.
Solution:   Add -I to $CFLAGS. (Ken takata)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index e213b80..3f05842 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -501,7 +501,7 @@
 #>>>>> end of choices
 ###########################################################################
 
-CFLAGS = -Iproto $(DEFINES) -pipe -march=$(ARCH) -Wall
+CFLAGS = -I. -Iproto $(DEFINES) -pipe -march=$(ARCH) -Wall
 CXXFLAGS = -std=gnu++11
 WINDRES_FLAGS = --preprocessor="$(WINDRES_CC) -E -xc" -DRC_INVOKED
 EXTRA_LIBS =
@@ -1049,7 +1049,7 @@
 	     $(PERLTYPEMAP) if_perl.xs -output $@
 
 $(OUTDIR)/if_perl.o:	auto/if_perl.c $(INCL)
-	$(CC) -c $(CFLAGS) -I. auto/if_perl.c -o $(OUTDIR)/if_perl.o
+	$(CC) -c $(CFLAGS) auto/if_perl.c -o $(OUTDIR)/if_perl.o
 
 
 $(OUTDIR)/if_ruby.o:	if_ruby.c $(INCL)
diff --git a/src/version.c b/src/version.c
index 350c8a7..1eab778 100644
--- a/src/version.c
+++ b/src/version.c
@@ -793,6 +793,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    480,
+/**/
     479,
 /**/
     478,