Ash POSIX shell on Plan9

This is a quick port of the Almquist shell to Plan9. Expect some roughness like calculator expressions (eg. `var = $(( 2 + 2 ))') not working. To build you need the old GNU gcc (gcc 3.0, sic!) from the sources repository. The makefile is also in BSD syntax so you need a BSD make like the original pmake or the NetBSD make called bmake. I have a port of pmake ready but I need to slightly clean it up before I publish it.

NB. The fact that I took two files (siglist.c and siglist.h) from Bash means that as a whole this falls under the GPL. The aim is however to make this a pure BSD licensed program again after I carry the port over to current Debian Ash aka Dash which ironically is still pure BSD like the original Ash despite being GNU affiliated.

// Jarkko Kniivilä