Remove unused main() args in many modules. This makes us closer to compiling cleanly with -Wunused (as used by -Wextra). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
opt: complete coverage, enhance opt_free_table. No point checking malloc failure in usage(), since we don't elsewhere. We get 100% coverage with -O (due to code elimination) or 64 bit.
iscsi, nfs, opt, tap: use config.h instead of defining _GNU_SOURCE.
opt: fix gcc -O3 warnings.
opt: wean off getopt_long, beef up tests. Doing our own parsing lost a few lines of code, too. Our coverage is over 99% now.
opt: add opt_log_stderr_exit helper, and opt_usage NULL option. The former encapsulates a common "just exit on error" case, the latter avoids having to repeat the extra usage string. (We actually would have crashed before if someone passed NULL there, even though the documentation said you could).
opt: Put actual options inside names. This is more explicit than separate short and long (great for grep!) and simpler.