The only way the setitimer call can fail is if the unsigned number of seconds is
too large to fit in the kernel's signed number of seconds. If you schedule a
68-year alarm, glibc will fail by returning 0 and BSD will fail by returning -1.
Change-Id: Ic3721b01428f5402d99f31fd7f2ba2cc58805607
Also undo some of the mess where we have OpenBSD <stdio.h> but a mix of
different BSD's implementations.
In this first pass, I've only moved easy OpenBSD stuff.
Change-Id: Iae67b02cde6dba9d8d06fedeb53efbfdac0a8cf6