firefox dumps core on amd64

[Kurt Schreiner <ks%ub.uni-mainz.de@localhost>]

Hi,

trying to run firefox build from pkgsrc on -current amd64 fails w/
SIGSEGV in __nanosleep50:

 [...]
 28685      1 xulrunner-bin NAMI  
"/home/ks/.mozilla/firefox/rspqb1xe.default/permissions.sqlite-jou
rnal"
 28685      1 xulrunner-bin RET   open 21/0x15
 28685      1 xulrunner-bin CALL  __nanosleep50(0x7f7fffffab20,0)
 28685      1 xulrunner-bin RET   __nanosleep50 -1 errno 22 Invalid argument
 28685      1 xulrunner-bin PSIG  SIGSEGV caught handler=0x7f7ff5cb0a02 
mask=(1,2,3,4,5,6,7,8,10,11,
12,13,14,15,16,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,4
6,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63): code=SEGV_ACCERR, 
addr=0x7f7fffffab20, trap=6
)
 28685      1 xulrunner-bin CALL  unlink(0x7f7ff7b1f520)
 28685      1 xulrunner-bin NAMI  
"/home/ks/.mozilla/firefox/rspqb1xe.default/lock"
 28685      1 xulrunner-bin RET   unlink 0
 28685      1 xulrunner-bin CALL  
__sigaction_sigtramp(SIGSEGV,0x7f7ff6ecd920,0,0x7f7feca88400,2)
 28685      1 xulrunner-bin RET   __sigaction_sigtramp 0
 28685      1 xulrunner-bin CALL  __sigprocmask14(2,0x7f7fffffa5c0,0)
 28685      1 xulrunner-bin RET   __sigprocmask14 0
 28685      1 xulrunner-bin CALL  _lwp_self
 28685      1 xulrunner-bin RET   _lwp_self 1
 28685      1 xulrunner-bin CALL  _lwp_kill(1,0xb)
 28685      1 xulrunner-bin RET   _lwp_kill 0
 28685      1 xulrunner-bin PSIG  SIGSEGV SIG_DFL: code=SI_LWP sent by 
pid=28685, uid=777)
 28685      5 xulrunner-bin RET   ___lwp_park50 -1 errno 4 Interrupted system 
call
 28685      2 xulrunner-bin RET   poll -1 errno 4 Interrupted system call
 28685      3 xulrunner-bin RET   ___lwp_park50 -1 errno 4 Interrupted system 
call
 28685      4 xulrunner-bin RET   ___lwp_park50 -1 errno 4 Interrupted system 
call
 28685      1 xulrunner-bin NAMI  "xulrunner-bin.core"

I tried on two machines (one "real", one virtual) build from -current
as of an hour or so ago, xulrunner/firefox (re)build after rebuilding
and installing kernel and userland...

Any idea anyone whats goin on here? 

FWIW: Doing all the same steps on i386 leads to a working firefox...

Kurt