tools: add gnulib source

tools: add gnulib source

By having a local copy of gnulib, we can:
import the latest macro fixes into any package,
get rid of some statically stored macros that were otherwise missing,
bootstrap GNU tools with the latest relevant source
without having to wait for a release or rely on git submodules,
and possibly more...

The patch assists in bootstrapping by ignoring
the building of po files using gettext,
and also to allow a user-defined path to a program
to include parameters.

Signed-off-by: Michael Pratt <mcpratt@pm.me>