What does BATCH=yes really mean? (portmaster vs. bpm)

[Sam Lawrance]

Just hours ago I went to give sysutils/portmaster a try. An OPTIONS  
selection screen appeared on the first run.  I then ran the following  
command, thinking I could leave portmaster going and wander off:

portmaster -a -m "BATCH=yes"

Again an OPTIONS dialog appeared.  It seems that portmaster was  
running the command 'make BATCH=yes config', which is an interactive  
operation.  I'm not sure whether this is incorrect behaviour from the  
'config' target, or perhaps a deficiency in portmaster.  I'm sure  
there are easy ways to work around the problem, but special cases are  
pesky.

Perhaps there are other targets for which this behaviour would be  
unexpected.  Thoughts?