[tex-live] inclusion of libraries

[Jonathan Kew]

A question regarding libraries and linkage preferences, as I'm  
working towards including XeTeX source in TeX Live:

xetex depends on several libraries that are not currently included in  
the TL source tree. Currently, it links statically with several ICU  
libraries and with SIL's TECkit, and dynamically with the system's  
installed versions of fontconfig, freetype, imagemagick, and zlib.

(For the ICU libraries, libicu*.a, xetex has a private version  
because it is using a slightly modified version of the ICU layout  
engine with some added features, so the question of using an  
installed copy does not arise. In the case of libTECkit, this is a  
small library that is unlikely to be widely installed, so it seems  
simplest to just use a private copy.)

TL practice seems to be to include source of all required libraries  
in texk/lib, and to link statically so as to produce self-contained  
binaries, though there are configure options such as --with-system- 
zlib, etc., to use installed libraries rather than TL private copies.

So for TL purposes, should I plan to include all these libraries in  
texk/lib, and default to building and using these versions unless -- 
with-system-.... is specified? Or is it acceptable to rely on  
installed copies of some or all of these, and leave it to packagers  
to ensure that the prerequisites are available, as part of the  
package management and installation function?

Guidance would be welcome.... thanks!

Jonathan