something'.
It should not link at least for '-x c-header' and '-x c++-header', and maybe
link for '-x c' or '-x c++', but we expect noone will be linking using these
later strings.
Adding opencv, which required '-x c-header' working, and that's why I have
updated gcc wrapper.
svn path=/nixpkgs/branches/stdenv-updates/; revision=19491
