Make create_manpage_completions not generate empty files
https://github.com/fish-shell/fish-shell/issues/506
Tweak test_fork to exercise strerror
Don't call strerror or perror after fork, it's unsafe. Added safe_strerror and safe_perror replacements.
Fixes https://github.com/fish-shell/fish-shell/issues/495
Fixed a minor typo: standrard -> standard