libutil: Make stosb take size_t instead of int
libutil: Make stosb take size_t instead of int

Well that sucked.  This caused really large memsets to misbehave.

aclements/sv6,bowlofstew/sv6,aclements/sv6,aclements/sv6,aclements/sv6,aclements/sv6,bowlofstew/sv6,bowlofstew/sv6,bowlofstew/sv6,bowlofstew/sv6