[Ecls-list] Patches for defsystem and fixes for ECL

[Juan Jose Garcia Ripoll]

I think this time I made the patches right. There were some issures with the 
only IN-PACKAGE form in defsystem.lisp, because it uses non-standard 
arguments :nicknames, or something like that. I had also forgoten to add 
support for invoking unix shell commands via #'si:system.

The following had to be fixed in ECL

+ FILENAME-NAMESTRING was broken

+ WITH-COMPILATION-UNIT now implemented and does nothing.

+ ENSURE-DIRECTORIES-EXIST now implemented.

+ New logical hostname "HOME:" has the translation
	("**/*.*" "~/**/*.*")

+ Wildcard-directory "**" now works... I hope. At least someting like 
"home:dira;dirb;dirc;name.lisp" gets properly translated to 
"~/dira/dirb/dirc/name.lisp".

Best regards

Juanjo