* cygtls.h (_cygtls::init_exception_handler): Eliminate argument.

* cygtls.h (_cygtls::init_exception_handler): Eliminate argument.
(_cygtls::andreas): Convert to a pointer.
(san): Convert to a real class with methods.  Use a linked list to keep track
of previous handlers on the "stack".
(myfault): Rewrite to use new san class rather than calling directly into
_cygtls.
* cygtls.cc (_cygtls::init_exception_handler): Just assume that we're always
using the standard exception handler.
(_cygtls::init_thread): Reflect loss of argument to init_exception_handler.
* dcrt0.cc (dll_crt0_1): Ditto.
* dfcn.cc (dlopen): Ditto.
(dlclose): Reset the exception handler after FreeLibrary.
* dll_init.cc (dll_list::detach): Make sure that the exception handler is
initialized before calling destructors.
* exceptions.cc (_cygtls::handle_exceptions): Accommodate new andreas pointer.
* thread.cc (verifyable_object_isvalid): Pass objectptr to faulted for explicit
NULL pointer checking.
* tlsoffsets.h: Regenerate.