Re: configuring live images

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

> I have found it useful to configure at least parts of the contents of
> live images produced with the 'live-image' target of build.sh.  In
> particular, I have found it useful to configure the exact MBR bootcode
> and the installboot options.  Consequently, I suggest (something like)
> the attached patch as a means of allowing greater flexibility.

Looks good, but I'd like to:
 - add a new variable MBR_BOOT to specify MBR bootcode passed to fdisk(8)
   rather than reusing current USE_MBR because there are several ports
   which require MBR partitioning but no MBR bootcode
   (only amd64/i386/landisk have mbr bootcode)
 - use explicit INSTALLBOOTOPTIONS rather than BOOTOPTIONS

I'll commit the similar changes if no further opinions.
---
Izumi Tsutsui