Updated Rakefile.
Updated Rakefile.

Updated Rakefile for gnu99 (C99) extensions and to ensure that
the ObjC2 runtime is used by mininush on Leopard.

Verified on 10.5 only.  I expect there are problems on 10.4.

gcbeyond/nu,hodgeswt/nu,nulang/nu,jsyedidia/nu,nulang/nu,jqk6/nu,alloy/nu,spotify/nu,timburks/nu,hodgeswt/nu,jsyedidia/nu,spotify/nu,spotify/nu,gcbeyond/nu,timburks/nu,nulang/nu,hodgeswt/nu,hodgeswt/nu,jsyedidia/nu,jqk6/nu,jqk6/nu,gcbeyond/nu,timburks/nu,heiko-henrich/nutor,heiko-henrich/nutor,gcbeyond/nu,heiko-henrich/nutor,jsyedidia/nu,spotify/nu,jqk6/nu,jsyedidia/nu,alloy/nu,heiko-henrich/nutor