$ uname -mrs
FreeBSD 5.3-RELEASE-p10 i386

/usr/local/share/aclocal$ ls -l glib*
-r--r--r--  1 root  wheel  8442 Dec 31  2004 glib.m4
-r--r--r--  1 root  wheel   983 Jan  6  2005 glibc21.m4

/usr/local/lib$ ls -l libglib*
lrwxr-xr-x  1 root  wheel      11 Mar 28 15:38 libglib.a -> libglib12.a
-rw-r--r--  1 root  wheel  209196 Dec 31  2004 libglib12.a
lrwxr-xr-x  1 root  wheel      14 Dec 31  2004 libglib12.so -> libglib12.so.3
-rwxr-xr-x  1 root  wheel  176093 Dec 31  2004 libglib12.so.3

/usr/local/lib$ glib-config --version
1.2.10

~/irssi-0.8.10$ ./configure --prefix=/usr/local --sysconfdir=/usr/local/etc
<snip>
checking whether GLib is unpacked to irssi dir... no
./configure: line 7165: syntax error near unexpected token `1.2.0,,,'
./configure: line 7165: `      AM_PATH_GLIB(1.2.0,,, $glib_modules)'