On the i386, the set/longjmp() functions use sigblock() and
sigsetmask() to store the signal state.  These use an int, not the
now-longer sigset_t, which means signals > 31 won't properly be saved
or restored.

On the alpha, once again setjmp() and friends call sigblock,
__sigaltstack14(), and the like to save state.  It uses sigreturn() to
return to the setjmp() point, however.

Does this seem slightly wrong, or am I confused?

--Michael