autoconf probe macro to determine how to use Expat. Anonymous contribution: SF patch #438892.
autoconf probe macro to determine how to use Expat.
Anonymous contribution: SF patch #438892.

libexpat/libexpat,tiran/expat,tiran/expat,tiran/expat,libexpat/libexpat,libexpat/libexpat,tiran/expat,libexpat/libexpat,libexpat/libexpat,libexpat/libexpat