Vex currently has duplicate filenames in different directories, eg. priv/guest-{x86,amd64,ppc,arm}/toIR.c. This confuses automake. It would be better to rename these files to avoid the duplication. Julian has to do this because it's in Vex. Makefile.vex.am will need updating accordingly; there are XXX marks indicating the temporary workarounds that are removable.