cmake: Define HAVE_PRCTL, HAVE_RAISE according to existing checks
Otherwise test-segfault will not be able to disable core dumps, making it extremely slow and noisy to run the tests under cmake. I added the missing checks in commit be55374f, but didn't add the corresponding symbols to config.h.cmake.
Closes: #227 (closed)
This branch also fixes the Autotools consistency check in out-of-tree (srcdir != builddir) builds.