In 2.017.11, I fixed the allegro version of asdf:run-shell-command on Unix. I also changed the way that same function is broken on Windows so at least it gives users some control, and behaves in a more regular way across implementations — i.e. some may call CMD, some may try to call sh instead, but at least you control exactly what's given to either interpreter, rather than have it garbled.
In the comments I also declare the function deprecated and recommend xcvb-driver:run-program/process-output-stream and derivatives as replacement.
Now to get xcvb-driver in Quicklisp and contact clients to stop using this mostly broken function...
—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org I don't know if might makes right, but lack of might sure makes lack of right.