Reokodoku

Also, there are optional enums that doesn't work. This patch should work (+ some test): ```diff diff --git a/lib/std/Build/Step/Options.zig b/lib/std/Build/Step/Options.zig index 8348d74..e05255c 100644 --- a/lib/std/Build/Step/Options.zig +++ b/lib/std/Build/Step/Options.zig @@ -272,12 +272,17...