[tlbuild] trial builds for TL'13

[Karl Berry]

    < Message 44 in Test.tex: User Regex:  intro..
    ---
    > Message 44 in Test.tex: User Regex: (null).

Well, after looking at the test file and script, evidently something is
going awry in the regex code, but there's no obvious way to debug
without being able to reproduce it, and it's not happening for me.

It seems our chktex uses the system regex functions instead of local
sources, so a 32-bit Mac-specific error isn't entirely a surprise.  I
wonder if the Mac requires some kind of compile-time or runtime setting.

If you're not up for debugging further yourself (Dick/Mojca/anyone),
about all I can suggest is to write to the chktex author, Jens T. Berger
Thielemann, email in all the source files (loath to reproduce it here).
Or his tracker at https://savannah.nongnu.org/bugs/?group=chktex.

The TeX Live configure (per chktex/configure.ac) always disables
HAVE_PCRE and always enables HAVE_POSIX_ERE.

Failing some fix, you should Build with --disable-chktex, since we
shouldn't distribute binaries that don't pass the tests.

karl