[tlbuild] Allow for building synctex as shared library

[Peter Breitenlohner]

On Sat, 28 Jun 2014, Norbert Preining wrote:

> The error while building detex is:
> Making all in detex
> make[4]: Entering directory '/src/TeX/debian/git/texlive-bin/Work/texk/detex'
> make  all-am
> make[5]: Entering directory '/src/TeX/debian/git/texlive-bin/Work/texk/detex'
> test -f detex-2.8/detex.c || /bin/sh ../../../texk/detex/../../build-aux/ylwrap ../../../texk/detex/detex-2.8/detex.l lex.yy.c detex-2.8/detex.c -- flex
> ../../../texk/detex/../../build-aux/ylwrap: 206: ../../../texk/detex/../../build-aux/ylwrap: cannot create ../detex-2.8/detex.c: Directory nonexistent
> Makefile:713: recipe for target 'detex-2.8/detex.c' failed
> make[5]: *** [detex-2.8/detex.c] Error 2

Hi Norbert,

(1) The were still a few changes for libsynctex, now applied as r34467.

(2) The shared library requires libz.so, i.e. will only be built with
     --enable-system-zlib, probably much of a restriction.

(3) Please read texmf-dist/doc/texlive/tlbuild/tlbuild.pdf, tlbuild.info,
     or 'Build system tools' in README.4layout.
     The fact that make tries to build detex.c from detex.l is due to bad
     timestamps.
     The only safe way is a fresh checkout from the SVN repository.
     Patching the released TL2014 build system is always done at your own
     risk!

Regards
Peter