libgo does not respect --disable-werror

https://bugs.gentoo.org/423153
http://gcc.gnu.org/PR53679

--- a/libgo/configure
+++ b/libgo/configure
@@ -13384,7 +13384,7 @@ done
 WARN_FLAGS='-Wall -Wextra -Wwrite-strings -Wcast-qual'
 
 
-WERROR="-Werror"
+WERROR=""
 
 
 glibgo_toolexecdir=no