OpenBSD: configure.ac changes
OpenBSD: fix src/lexer.l warnings
OpenBSD: remove GNUisms from lib/ Makefiles
OpenBSD: fetch-ieee.sh no longer requires bash
OpenBSD: make manpage target conditional on ronn program being installed
OpenBSD: fix some signed/unsigned warnings in cgen.c
OpenBSD: check HAVE_ALLOCA_H before including alloca.h
OpenBSD: uses MAP_ANON like OS X
OpenBSD: fix some warnings about unsafe functions