Log Message:
Update to 2.7:

New in 2.7:

* Support for platforms that follow POSIX:2008, not POSIX:2001.
* Support for MirBSD 10.
* Support for IRIX 5.3. Contributed by Eric Blake.
* On Linux platforms, libsigsegv now prefers the POSIX way of defining the
  signal handler over than the traditional one, when both are supported.
  As a consequence, on Linux/i386 and other Linux platforms, the type
  'stackoverflow_context_t' is now typedefed to 'ucontext_t *' rather than
  'struct sigcontext *'.