core dump in cvsup caused by _once()?

Since I installed a new world and kernel on November 26 I'm seeing
core dumps with cvsup, even though I reinstalled cvsup yesterday.

Here the output from a gdb session without any debugging symbols:

Core was generated by `cvsup'.
Program terminated with signal 4, Illegal instruction.
Reading symbols from /lib/libz.so.5...(no debugging symbols found)...done.
Loaded symbols for /lib/libz.so.5
Reading symbols from /lib/libm.so.5...(no debugging symbols found)...done.
Loaded symbols for /lib/libm.so.5
Reading symbols from /lib/libc.so.7...(no debugging symbols found)...done.
Loaded symbols for /lib/libc.so.7
Reading symbols from /libexec/ld-elf.so.1...(no debugging symbols found)...done.
Loaded symbols for /libexec/ld-elf.so.1
#0  0x00000008009edcf7 in gmtime_r () from /lib/libc.so.7
(gdb) bt
#0  0x00000008009edcf7 in gmtime_r () from /lib/libc.so.7
#1  0x00000008009ed79e in gmtime_r () from /lib/libc.so.7
#2  0x00000008009ee420 in gmtime_r () from /lib/libc.so.7
#3  0x00000008009ee638 in gmtime_r () from /lib/libc.so.7
#4  0x00000008009f1988 in _once () from /lib/libc.so.7
#5  0x00000008009ed41f in timeoff () from /lib/libc.so.7
#6  0x00000008009eeca7 in gmtime () from /lib/libc.so.7
#7  0x00000000004a643a in calloc ()
#8  0x000000000043aec7 in ?? ()
#9  0x0000000000448eaa in ?? ()
#10 0x0000000000409ece in ?? ()
#11 0x00000000004191a4 in ?? ()
#12 0x0000000000417cbe in ?? ()
#13 0x000000000041529f in ?? ()
#14 0x0000000000414d7a in ?? ()
#15 0x000000000049f980 in calloc ()
#16 0x000000000048fa3d in fnmatch ()
#17 0x00007fffffffd3e8 in ?? ()
#18 0x00007fffffffe950 in ?? ()
#19 0x00007fffffffea40 in ?? ()
#20 0x00007fffffffea28 in ?? ()
#21 0x0000000000000000 in ?? ()
#22 0x0000000000000000 in ?? ()
#23 0x00001fa00000037f in ?? ()
#24 0x0000000000000000 in ?? ()
#25 0x00000000006476c0 in ?? ()
#26 0x00000000006476c0 in ?? ()
#27 0x0000000000494d89 in fnmatch ()
Previous frame inner to this frame (corrupt stack?)

Seems to me that _once() was a very recent addition.  Can't say for
certain whether this is the culprit, but it looks suspicious to me.

---
Gary Jennejohn