* external.cc (cygwin_internal): Add operation to retrieve a copy
of the EXCEPTION_RECORD from a siginfo_t *.
* include/sys/cygwin.h (cygwin_getinfo_types): Ditto.
* exception.h (cygwin_exception): Add exception_record accessor.
Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>