bug#16451: build newest guile on FreeBSD error

[z_axis]

hi,friends
After `git clone git://git.sv.gnu.org/guile.git`, `./autogen` reports:
m4: illegal option -- -
usage: m4 [-d flags] [-t name] [-gs] [-D name[=value]]...
       [-U name]... [-I dirname]... file...

on my FreeBSD 9.1 box.

Regards!