errors during buildworld

I am attempting to run 'make buildworld' using the FreeBSD 6.0-BETA5 source,
prior to this I completely removed and re-created /usr/src and /usr/obj and
downloaded the new source with cvsup. During the build I get the following
error, does anyone have any ideas what would be causing it or how to fix it?
 /usr/src/lib/libz/inflate.c:1086: internal compiler error: Segmentation
fault
<snip>
cc -fpic -DPIC -O2 -fno-strict-aliasing -pipe
-I/usr/src/lib/msun/../libc/include -I/usr/src/lib/msun/../libc/i386 -c
/usr/src/lib/msun/i387/s_copysignl.S -o s_copysignl.So
cc -O2 -fno-strict-aliasing -pipe -I/usr/src/lib/msun/../libc/include
-I/usr/src/lib/msun/../libc/i386 -c /usr/src/lib/msun/i387/s_floorl.S
cc -fpic -DPIC -O2 -fno-strict-aliasing -pipe
-I/usr/src/lib/msun/../libc/include -I/usr/src/lib/msun/../libc/i386 -c
/usr/src/lib/msun/i387/s_floorl.S -o s_floorl.So
cc -O2 -fno-strict-aliasing -pipe -I/usr/src/lib/msun/../libc/include
-I/usr/src/lib/msun/../libc/i386 -c /usr/src/lib/msun/i387/s_scalbnl.S
cc -fpic -DPIC -O2 -fno-strict-aliasing -pipe
-I/usr/src/lib/msun/../libc/include -I/usr/src/lib/msun/../libc/i386 -c
/usr/src/lib/msun/i387/s_scalbnl.S -o s_scalbnl.So
cc -O2 -fno-strict-aliasing -pipe -I/usr/src/lib/msun/../libc/include
-I/usr/src/lib/msun/../libc/i386 -c /usr/src/lib/msun/i387/s_truncl.S
cc -fpic -DPIC -O2 -fno-strict-aliasing -pipe
-I/usr/src/lib/msun/../libc/include -I/usr/src/lib/msun/../libc/i386 -c
/usr/src/lib/msun/i387/s_truncl.S -o s_truncl.So
building static m library
building shared library libm.so.4
ranlib libm.a
sh /usr/src/tools/install.sh -C -o root -g wheel -m 444
libm.a/usr/obj/usr/src/tmp/usr/lib
sh /usr/src/tools/install.sh -C -o root -g wheel -m 444
/usr/src/lib/msun/i387/fenv.h /usr/src/lib/msun/src/math.h
/usr/obj/usr/src/tmp/usr/include
sh /usr/src/tools/install.sh -s -o root -g wheel -m 444
libm.so.4/usr/obj/usr/src/tmp/lib
ln -fs /usr/obj/usr/src/tmp/lib/libm.so.4
/usr/obj/usr/src/tmp/usr/lib/libm.so
1 error
*** Error code 2
1 error
*** Error code 2
1 error
*** Error code 2