Commit Briefs
minor tweaks
* don't need to export optarg/optind * use an easier to read cast for indirect array access
rework the build system and bump version
let's use OpenBSD' bsd.xconf.mk and bsd.prog.mk
rewrite readlines
use getline instead of rolling a custom version; swap the argument and return type to avoid being a "three star" programmer. Then, gargabe collect the now unused read_stdin, STDIN_CHUNKS and LINES_CHUNK.