
add a __bounded() define as a shortcut for out bounds-checking attributes
that turns itself off when not compiling with gcc

add __warn_unused_result as a shortcut to the __warn_unused_result__
attribute

ok martynas@

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