Require texi2dvi in tests, makeinfo may not be enough. * tests/txinfo16.test: RHEL 5.2 has makeinfo and texi2dvi in separate packages, so also list the latter as required, as the test generates DVI and/or PDF output (through distcheck). * tests/txinfo18.test: Likewise. * tests/txinfo21.test: Likewise. * tests/txinfo22.test: Likewise. * tests/txinfo3.test: Likewise. * tests/version7.test: Likewise. * THANKS: Update. Report by Alexander Martens. Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>