Force

I want to cross-compiling Perl-GD for an embedded Linux (see www.buildroot.net), so autoconfigure can not work for me.
I use the option `ignore_missing_gd` (and `lib_*_path`), when I call the C cross compiler, the include paths and lib paths must not contain any path of my host machine. So @INC and @LIBPATH must stay empty.

(see my current work at https://github.com/fperrad/br/tree/dancer2/dancer2/package/perl-gd)