component/messagepack: update bundled GNU Config

component/messagepack/buildout.cfg

 [buildout]
+extends = ../gnu-config/buildout.cfg
+
 parts = messagepack
 
 # XXX: Do not reuse. It should be trashed along with kumofs.
@@ -10,5 +12,6 @@ recipe = slapos.recipe.cmmi
 shared = true
 url = http://downloads.sourceforge.net/project/msgpack/msgpack/cpp/msgpack-0.5.4.tar.gz
 md5sum = 18d96a3178f7cad73c0ca44f6284ae7d
+pre-configure = cp -f ${gnu-config:location}/config.sub ${gnu-config:location}/config.guess ac/
 configure-options =
   --disable-static