Glibc with shell

On linux, combine the final `glibc` with the final `bash`, and use the `sh` from `bash` for `glibc`'s `system(3)`, `popen(3)`, etc.

Fixes #1424
This worries me a little, doesn't this match `.*/bin/sh.*`? I'd feel safer with a `\w` kind of delimiter but I think sed doesn't do that :-/