ninja doesn't work (ninja: fatal: posix_spawn: Invalid argument)

[skyem123]

I'm not sure if this is the correct place for this as there is an issue on the main WSL thing, but I'm reporting this anyway in the hope that it can help.
Whenever the ninja build tool tries to start another program it crashes with the error ninja: fatal: posix_spawn: Invalid argument.

A good / simple way to reproduce is to compile ninja from source.
I have also put some more details at microsoft/WSL#1306 (comment).

[patstew]

I've fixed this problem with spawn by backing out the change in glibc mentioned here microsoft/WSL#1878
The package is available on the AUR here: https://aur.archlinux.org/packages/glibc-wsl/
You need to build it on a system that already has a working glibc, e.g. a proper linux install.