Bro compilation problem under Gentoo 2006.1

Hello,
  I'm trying to compile Bro 0.9a11 under Gentoo 2006.1 but I always get
this error:

cd . && /bin/sh /home/wildchild/bro/bro-0.9a11/missing --run autoheader
configure.in:441: warning: AC_TRY_RUN called without default to allow cross
compiling
/usr/bin/autoheader-2.13: Symbol `ns_msg' is not covered by
/usr/share/autoconf/acconfig.h
make: *** [stamp-h.in] Erreur 1

Any idea?

Thanks

Gabriel Lavoie