Add machine/exec.h to allow machine to set ELFSIZE before using ifdefing code based on if that define exists. OKed by theo.
Add machine/exec.h to allow machine to set ELFSIZE before using
ifdefing code based on if that define exists.
OKed by theo.

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