Re: Should lisp/Makefile.in custom-deps be using EMACS or emacs?

[Richard Stallman]

    >From an strace it looked like this arrangement was causing my
    /usr/share/... custom-deps.el to shadow the newer one in ./lisp

The information you omitted with that "..." is crucial information.
Precisely what directory was that file in?  And what exactly was the
value of load-path?

      I had just
    presumed that the build process would prefer the source tree versions
    of the .el files, and so was surprised when my changes to
    ./lisp/custom-deps.el didn't have any (immediate) effect.

Indeed, for an uninstalled Emacs the files in your source tree should
take precedence over installed files.  Only the site-lisp directories
should take precedence over your source tree.  If that is working
properly, the problem won't happen.  So we need to see if it is
not properly set up.