wincred: avoid overwriting configured variables

diff --git a/contrib/credential/wincred/Makefile b/contrib/credential/wincred/Makefile
index 39fa5e0c5921124e6331c9008d918e27991f7c85..6e992c08667d0b2b6a3c2d42314e3f500eb7502a 100644 (file)
--- a/contrib/credential/wincred/Makefile
+++ b/contrib/credential/wincred/Makefile
@@ -1,12 +1,12 @@
 all: git-credential-wincred.exe
 
-CC = gcc
-RM = rm -f
-CFLAGS = -O2 -Wall
-
 -include ../../../config.mak.autogen
 -include ../../../config.mak
 
+CC ?= gcc
+RM ?= rm -f
+CFLAGS ?= -O2 -Wall
+
 prefix ?= /usr/local
 libexecdir ?= $(prefix)/libexec/git-core