* stdenv.mkDerivation now takes an optional attribute "meta" that

  contains arbitrary information about a package, like this:

  meta = {
    homepage = "http://gcc.gnu.org/";
    license = "GPL/LGPL";
    description = "GNU Compiler Collection, 4.0.x";
  };

  The "meta" attribute is not passed to the actual derivation
  operation, so it's not a dependency --- changes to "meta" attributes
  don't trigger a recompilation.

  Now we have to standardise some useful attributes ;-)

svn path=/nixpkgs/branches/usability/; revision=5024