[XeTeX] updated ICU library in XeTeX - please test

[Jonathan Kew]

I have just updated the xetex subversion repository at http://scripts.sil.org/svn-public/xetex/TRUNK 
  to build xetex using ICU release 4.0 in place of release 3.8.1.

It would be helpful if some people can build and test this, especially  
working with OpenType fonts (both "pro" Latin-script fonts with  
various features, and non-Latin scripts such as CJK, Arabic, and Indic  
writing systems). If possible, I'd like to apply this update to the  
TeX Live sources as well, in time for the final TL 2008 binary builds,  
so if there are any problems arising from the update, we need to know  
about them ASAP.

I'm not really expecting to see regressions -- in fact, many of the  
ICU layout engine updates had been applied to the 3.8.1 sources in  
xetex already -- but would appreciate any further testing.

Thanks,

JK