The shared library is part of /usr/ports/devel/glib20. Do you have it installed (pkg_info should show it as glib-2.16.5)?
Code:
# ls -al /usr/local/lib/libgobject-2.0.*
-rw-r--r-- 1 root wheel 370162 Aug 16 02:08 /usr/local/lib/libgobject-2.0.a
-rwxr-xr-x 1 root wheel 984 Aug 16 02:08 /usr/local/lib/libgobject-2.0.la
lrwxr-xr-x 1 root wheel 19 Aug 16 02:08 /usr/local/lib/libgobject-2.0.so -> libgobject-2.0.so.0
-rwxr-xr-x 1 root wheel 251326 Aug 16 02:08 /usr/local/lib/libgobject-2.0.so.0
lrwxr-xr-x 1 root wheel 19 Aug 26 13:18 /usr/local/lib/libgobject-2.0.so.400 -> libgobject-2.0.so.0