test for valgrind; valgrind is independent of g++.
(maintainer-check-posix): Add _POSIX2_VERSION=200112, to check
for compatibility with POSIX 1003.1-2001 (if running coreutils).
* tests/cxx-type.at (_AT_TEST_GLR_CXXTYPES): Port to stricter C++.
Use a destructor, so that we can expand the stack. Change
YYSTYPE to char * so that we can free it. Cast result of malloc.