i386 has MD TCB, so add the #define.  Not sure how I overlooked this for so long, but fixes SEGV on errno access with librthread.
i386 has MD TCB, so add the #define.  Not sure how I overlooked
this for so long, but fixes SEGV on errno access with librthread.

Apologies to jeremy@, todd@, robert@ and others for taking so long to track
this down

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars