[tex-live] Change 4742 -- web2c to "pre" 7.5.3.

[Olaf Weber]

I've just submitted change 4742, touching many files in the web2c
tree.  This, together a few changes elsewhere, brings my source tree
mostly in sync with the repository.  Barring calamities, this is the
web2c 7.5.3 code base.  The change entry:

        A huge change, to bring the TeX-live source in sync with my
        working sources for web2c.  These changes implement:
        - ini* and vir* links are no longer created
        - xord/xchr/xprn are always dumped
        - 8bits option
        - pool_name and engine_name parametrization of mf and mp
        - halt-on-error option
        - setting $engine in the environment
        - all formats have .fmt extension
        - quoted filenames so filenames with spaces can work
        Some of these changes touch a lot of files at the same time.
        They also spilled over into omega and aleph.
        eomega builds are probably broken at this point

Please note that last point: changes I made required changes to aleph,
omega, and pdf*tex, or their builds would fail.

-- 
Olaf Weber

               (This space left blank for technical reasons.)