include CFLAGS in gnome askpass targets

from Fedora
diff --git a/contrib/Makefile b/contrib/Makefile
index c6c48e7..eaf7fe2 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -4,12 +4,12 @@
 	@echo "Valid targets: gnome-ssh-askpass1 gnome-ssh-askpass2"
 
 gnome-ssh-askpass1: gnome-ssh-askpass1.c
-	$(CC) `gnome-config --cflags gnome gnomeui` \
+	$(CC) $(CFLAGS) `gnome-config --cflags gnome gnomeui` \
 		gnome-ssh-askpass1.c -o gnome-ssh-askpass1 \
 		`gnome-config --libs gnome gnomeui`
 
 gnome-ssh-askpass2: gnome-ssh-askpass2.c
-	$(CC) `$(PKG_CONFIG) --cflags gtk+-2.0` \
+	$(CC) $(CFLAGS) `$(PKG_CONFIG) --cflags gtk+-2.0` \
 		gnome-ssh-askpass2.c -o gnome-ssh-askpass2 \
 		`$(PKG_CONFIG) --libs gtk+-2.0 x11`