write(2) lc_r problem

I'm trying to write a small sound application and run across a problem
on CURRENT.

It's very basic at the moment. It simply reads pcm data from a file and
uses write(2) on /dev/dsp.

But as soon as I link the program with -lc_r there's always about 1
second delay before a write call - which makes it pretty unusable for
playing sound.

It should be easy reproducable if you link audio/waveplay with -lc_r.

This doesn't happen in either FreeBSD 4.9, Knoppix or CURRENT if linked
with -lkse or -lthr.

Am I'm missing something basic when using write together with lc_r or
ist this a bug in CURRENT?