Re: master 2c79a8f 2/2: Use posix_spawn if possible.

[Saulius Menkevicius]

Hi,

I know this has been merged a couple of months ago to `master` but I 
would like to report breakage that occurs due to that commit.

We have csharp-ls (C#) and fsautocomplete (F#) LSP servers that stopped 
working with that commit (git-bisected to 
a60053f8368e058229721f1bf1567c2b1676b239).

I did not delve too much into the details or prepare a minimal test case 
but this appears to be an interplay between dotnet runtime (v6) and 
posix_spawn.

Not sure if that warrants a revert but just a heads-up.

-Saulius