[exim] Compiling exim 4.50 on the Hurd

Hello,

Seeing item 62 in the ChangeLog for 4.50, I decided to give it a try on
my GNU/Hurd machine ;)

I just had to modify the scripts/os-type to add a case for GNU, because
it was otherwise detecting it as Linux.

Otherwise, it compiled just fine and so I thought it would be a good
opportunity to mention it here ;)

Best regards,

Chris

-- 
 ,''`.  Christopher `Physicman' Bodenstein <cb@???>
 : :' :  Physicman.Net     :   http://www.physicman.net/ 
 `. `'   Debian GNU/Hurd   :   http://www.debian.org/ports/hurd/
   `-    The Hurd wiki     :   http://hurd.gnufans.org/