Make soft links in src for module source files, if built in to the executable. This ensures that those files are built with the same compiler flags as all other source files. See these xemacs-beta messages: <CAHCOHQn+q=Xuwq+y68dvqi7afAP9f-TdB7=8YiZ8VYO816sjHg@mail.gmail.com> <f5by5ejqiyk.fsf@calexico.inf.ed.ac.uk>

This directory contains the source code for the architecture-dependent
files that go in ../arch-lib.  At present, these are mostly utility
programs used by Emacs.