Fix XFAIL_TESTS matching for NetBSD ksh. * lib/am/check.am (check-TESTS): In the case patterns for XFAILed tests, add literal bracket expression for matching whitespace, as NetBSD 4.99.54 ksh does not understand a bracket expression resulting from variable expansion. * README: Explain how to run the Automake test suite, including setting MAKE to test gmake. Report by Patrick Welche.