Cannot redirect stderr using posix_spawn

[leorize]

Run examples with

$ gcc -o spawnredir spawnredir.c
$ gcc -o err err.c
$ ./spawnredir

Expected: no output, a file named errlog appears contains the string something

Reality: the program outputs something, errlog file appears but empty

[korli]

Fixed in ​20694a04585f349f3815d13c1fbbccee66c782d6 (no hrev generated).