grub2 boot root-on-zfs errors

[Beeblebrox <zaphod@berentweb.com>]

I had tried to build from source several months back, and had a
discussion on the FreeBSD mail list about the issue. The problem was
that the config is set as no_libzfs_support. What is the way to
correct this (need zfs library)?)
GRUB2 will be compiled with following components:
Platform: i386-pc
With devmapper support: No (need libdevmapper header)
With memory debugging: No
With disk cache statistics: No
With boot time statistics: No
efiemu runtime: No (cannot compile with -m64 -mcmodel=large
-mno-red-zone -nostdlib)
grub-mkfont: Yes
grub-mount: No (need FUSE library)
starfield theme: No (No DejaVu found)
With libzfs support: No (need zfs library)
Build-time grub-mkfont: No (no fonts)
Without unifont (no build-time grub-mkfont)
With liblzma from -llzma (support for XZ-compressed mips images)
------------------------------------------------

Other notes as information for any future reader:
*  I had to instal devel/bzr (the main bazaar port) since *BSD does
not have any git->bzr translator. The only tool at the date of this
message is bzr->git, which requires the base bzr port to be installed
anyway.
* devel/autogen needs to be installed
* I had to disable line 6014 in config, because it gives incorrect error:
# as_fn_error $? "flex is too old. GRUB requires 2.5.35 or above" "$LINENO" 5
flex --version  =>  flex version 2.5.4,  PORTVERSION=    2.5.37
FreeBSD-9.2-stable_amd64