nanobsd.sh change: configurable boot0 loader and configuration

[Adrian Chadd]

And here's a simple documentation patch for my nanobsd changes.

Index: share/man/man8/nanobsd.8
===================================================================
RCS file: /home/ncvs/src/share/man/man8/nanobsd.8,v
retrieving revision 1.2
diff -u -r1.2 nanobsd.8
--- share/man/man8/nanobsd.8    5 Nov 2006 20:08:58 -0000       1.2
+++ share/man/man8/nanobsd.8    20 Apr 2007 01:51:24 -0000
@@ -197,6 +197,18 @@
 Path to the source tree used to build the image.
 .It Va NANO_KERNEL
 Name of the kernel configuration file used to build the kernel.
+.It Va NANO_BOOT0CFG
+Controls the options passed to
+.Xr boot0cfg 8
+; these dictate boot0's behaviour.
+.It Va NANO_BOOTLOADER
+The boot0 loader to use relative to the ${NANO_WORLDDIR} variable.
+This defaults to
+.Pa boot/boot0sio
+and should be overridden to
+.Pa boot/boot0
+to provide a VGA
+console.
 .It Va CONF_BUILD
 Options passed to the
 .Cm buildworld
@@ -293,6 +305,8 @@
 .Ed
 .Sh SEE ALSO
 .Xr make.conf 5 ,
+.Xr boot 8 ,
+.Xr boot0cfg 8 ,
 .Xr picobsd 8
 .Sh HISTORY
 The