This happens while build on Hardened Gentoo Linux, kernel 2.6.28-hardened-r9, glibc-2.9_p20081201-r2, gcc-4.3.4.
>>> cd /var/tmp/portage/dev-util/plan9port-99999999/work/plan9/src/cmd/9660srv; mk all
9l -o o.9660srv main.o 9660srv.o xfile.o iobuf.o data.o
/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/../../../../i686-pc-linux-gnu/bin/ld: errno: TLS definition in /lib/libc.so.6 section .tbss mismatches non-TLS reference in main.o
/lib/libc.so.6: could not read symbols: Bad value
collect2: ld returned 1 exit status
mk: 9l -o o.9660srv ... : exit status=exit(1)
mk: for i in ... : exit status=exit(1)
mk: for i in ... : exit status=exit(1)
Trivial patch attached.