xcompile: Don't print error messages

Don't print error messages if an unpatched clang is detected.

Change-Id: If77722a40a59e99f01d121a0c43999f05f3c4421
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: http://review.coreboot.org/10554
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/util/xcompile/xcompile b/util/xcompile/xcompile
index 07bcde7..7363b19 100755
--- a/util/xcompile/xcompile
+++ b/util/xcompile/xcompile
@@ -166,7 +166,7 @@
 
 detect_compiler_runtime() {
 	test -z "$CLANG" || \
-	CC_RT_CLANG="`${CLANG} ${CFLAGS} -print-librt-file-name`"
+	CC_RT_CLANG="`${CLANG} ${CFLAGS} -print-librt-file-name 2>/dev/null`"
 	test -z "$GCC" || \
 	CC_RT_GCC="`${GCC} ${CFLAGS} -print-libgcc-file-name`"
 }