diskparts misses the $sysname variable due to `rfork e' (preventing it to be inherited from parent, e.g. /rc/bin/termrc.)  Thus, explicitly define $sysname.

Notes:
Fri Apr 6 10:06:03 EDT 2007 rsc
    rfork e does not mean you can't inherit environment
    variables from the parent.  it means that the parent
    does not inherit changes back from the child.
    
    the real problem is that you are running the script
    without $sysname defined.
    


Reference: /n/sources/patch/applied/diskparts-sysname
Date: Tue Mar 27 17:08:32 CES 2007
Signed-off-by: zakame@spunge.org
Reviewed-by: rsc

--- /rc/bin/diskparts	Tue Mar 27 17:06:02 2007
+++ /rc/bin/diskparts	Tue Mar 27 17:05:52 2007
@@ -9,6 +9,8 @@
 			disk/prep -p $part >$disk/ctl >[2]/dev/null
 }
 
+sysname=`{cat /dev/sysname}
+
 # set up any fs(3) partitions
 if (test -r	/cfg/$sysname/fsconfig)
 	read -m /cfg/$sysname/fsconfig >/dev/fs/ctl