make touch avoids rebuilding "pgen and stuff", and just uses what was checked out or provided in the tarball.  The release tarballs are supposed to have the time stamps in the correct order so that the compiletime/boostrapping utilities don't get built/rebuilt.

So for cross compilation, you should be able to use the existing files to build the target python.  If you then also want pgen *on the target*, you will need to build it for the target.  Like I said, I don't have much experience with this stuff, but if I understand correctly, you only really the utilities if you want to be able to do development *of python* on the target.

So, if running make in cross-compile "mode" (whatever that looks like, I have no clue) tries to rebuild pgen in your scenario, then *that* is what needs to be fixed, I think.

Of course, I could be completely wrong, which is why I've been pretty tentative about handing out advice :)