The tests use pgrep which is not packaged for darwin yet as we are
lacking some private / non open source headers for it to compile.
May be resolvable in the future.
A script used at test time in HTF assumes that you have GNU coreutils
installed in a manner where all executables are prefixed with a `g`.
Since we use GNU coreutils in the stdenv anyways, this is not necessary
and needs to be patched out.