I'll look into making a pull request to druntime about posix_spawn [..]
Here's the full deal: https://github.com/dlang/druntime/pull/2329/files with support for: Linux Glibc Linux Bionic libc Linux Musl libc Linux uClibc Darwin (macOS and iOS) FreeBSD NetBSD OpenBSD DragonFlyBSD Solaris/Illumos (thanks @n8sh!)
