Merge my experimental branch's testcases into the trunk. In addition, also change the infrastructure of testcases slightly so TESTS is not set directly by $(check_PROGRAMS) for future expansion. git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@2749 4407c894-4637-0410-b4f5-ada5f102cad1