Grep on Solaris does not support -q.
Reported by Summum Bonum.
* NEWS: Add a stub for 2.4.2.
* THANKS: Add Summum Bonum.
* tests/atlocal.in (EGREP): New.
(CC, CXX, XSLTPROC): Make it possible to override them via
envvars.
* tests/java.at: Use $EGREP instead of egrep.
Use AT_CHECK's ignore instead of grep's -q.