x86_64 H.J. Lu <hjl.tools@gmail.com>
XCOFF Richard Sandiford <r.sandiford@uk.ibm.com>
XGATE Sean Keys <skeys@ipdatasys.com>
+ Xtensa Max Filippov <jcmvbkbc@gmail.com>
Xtensa Sterling Augustine <augustine.sterling@gmail.com>
z8k Christian Groessler <chris@groessler.org>