Firefox/libthread_xu issue with pthread_attr_setschedparam

[Jordan Gordeev <jgordeev@xxxxxx>]

I have a Firefox problem caused by DragonFly and/or libthread_xu.
sched_get_priority_min(SCHED_OTHER) and 
sched_get_priority_max(SCHED_OTHER) return values PRIO_MIN (-20) and 
PRIO_MAX(20), both defined in sys/sys/resource.h.
When pthread_attr_setschedparam is called to set scheduling priority for 
scheduling policy SCHED_OTHER, the priority value is checked if it is 
within range by comparing it to THR_MIN_PRIORITY(0) and 
THR_MAX_PRIORITY(31), both defined in 
lib/libthread_xu/thread/thr_private.h. When a value in the range [-20; 
-1] is used, pthread_attr_setschedparam returns an error code of 
ENOTSUPP, which NSPR doesn't like. More precisely, when Firefox is 
compiled with the 'debug' pkgsrc option, an assert fails, abort() is 
called and a coredump written.