[Swan] [GW-C] thread-local storage vs. thread-specific data

[D. Hugh Redelmeier]

| From: D. Hugh Redelmeier <hugh at mimosa.com>

| xauth.c has a really complicated and badly written mechanism for keeping a 
| per-thread sigjmp_buf.
| 
| This would be greatly simplified and made more conventional by using 
| either thread-local storage vs. thread-specific data.

The use of thread-specific data would require the use of
pthread_getspecific(3p) in a signal handler, and that is not
legitimate.  So I think that thread-specific data is ruled out.

So: either we use thread-local storage, or we us some variant of the
current technique.