breakage in pcm/mixer.c

During a recent buildworld/make kernel, I got the following error:

------------------------------
cc -c -O -pipe -march=athlon-xp -Wall -Wredundant-decls -Wnested-externs 
-Wstrict-prototypes  -Wmissing-proto        types -Wpointer-arith -Winline 
-Wcast-qual  -fformat-extensions -std=c99  -nostdinc -I-  -I. -I/usr/src/sys 
-        I/usr/src/sys/contrib/dev/acpica -I/usr/src/sys/contrib/altq 
-I/usr/src/sys/contrib/ipfilter -I/usr/src/sys/c        ontrib/pf 
-I/usr/src/sys/contrib/dev/ath -I/usr/src/sys/contrib/dev/ath/freebsd 
-I/usr/src/sys/contrib/ngatm         -D_KERNEL -include opt_global.h 
-fno-common -finline-limit=8000  -mno-align-long-strings -mpreferred-stack-bo        
undary=2 -ffreestanding -Werror  /usr/src/sys/dev/sound/pcm/mixer.c
/usr/src/sys/dev/sound/pcm/mixer.c: In function `mixer_init':
/usr/src/sys/dev/sound/pcm/mixer.c:192: warning: `v' might be used 
uninitialized in this function
*** Error code 1

Stop in /usr/obj/usr/src/sys/YGGDRASIL.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
------------------------------

I'm upgrading from a May 22 -CURRENT. I do see some recent commits to 
pcm/mixer.c around that line, but have no idea if those could cause the 
problem. Any ideas?

Thanks,

-David