[tlbuild] luatex, xetex fixes

[Karl Berry]

There have been fixes to luatex and xetex over the last couple days.  If
you don't have the latest, please rebuild.  Looking at the timestamps, I
suspect this includes sparc-solaris, {i386,amd64}-netbsd, and
mipsel-linux, though I can't be sure.

As well as powerpc-linux (Thomas?) and {i386,x86_64}-solaris (Ettore?),
which haven't had initial builds yet.  Thanks.

K

P.S. For those doing their own commits: it is better not to install
xindy.mem when xindy itself does not change.  Unfortunately xindy.mem
(aka the clisp binary) includes a timestamp and so changes on every
build.  tl-update-bindir reverts it before committing unless xindy has
changed.