diff --git a/coreutils/cp.c b/coreutils/cp.c
index ae60623..b26c0e9 100644
--- a/coreutils/cp.c
+++ b/coreutils/cp.c
@@ -114,7 +114,7 @@
 # endif
 	);
 # if ENABLE_FEATURE_CP_REFLINK
-	BUILD_BUG_ON(OPT_reflink != FILEUTILS_REFLINK);
+	BUILD_BUG_ON((int)OPT_reflink != (int)FILEUTILS_REFLINK);
 	if (flags & FILEUTILS_REFLINK) {
 		if (!reflink)
 			flags |= FILEUTILS_REFLINK_ALWAYS;