libthr: Create landing pad in thr_once in C++ exceptionHEADmain

In _thr_once, if init_routine fails with exception, the stack allocate
__cup will become invalid when unwinder walk back and free the stack of
thr_once. This cause cleanup linked list be dangling. In here, we give
the cleanup function a landing pad so that we td can correctly point
to previous cleanup function.

Reviewed by:    kib
MFC after:      2 weeks
Differential Revision: https://reviews.freebsd.org/D61212

0 files changed, 0 insertions, 0 deletions