libgccjit: don't try to enter into non-existent $lib output

Fixes build failure on `staging-next` introduced by commit c817efe6
("gcc: extend stripping of .a libraries and .o objects"):

    ...-bootstrap-stage3-stdenv-linux/setup: line 106: pushd: no other directory

Build failure happens because `libgccjit` has different `outputs` layout
compared to the rest of `gcc` derivations:

     outputs = [ "out" "man" "info" ] ++ lib.optional (!langJit) "lib";

The change carves out `$lib` lib handling part to avoid `gcc` rebuild
in `staging-next`.

0 files changed, 0 insertions, 0 deletions