display defaults for PREFIX and MAXAGENTS in make help

[cgzones]

No description provided.

[awiddersheim]

I am wondering if it would be better to use the variables ($PREFIX and MAXAGENTS) when displaying the defaults.

Someone could do something like make PREFIX=blah help and see the wrong data. Perhaps setting a DEFAULT_PREFIX variable that gets set to the PREFIX variable. Start to complicate the code then. Just thinking out loud.

[cgzones]

I'm not convinced: in my opinion make help should display the defaults for typing type make TARGET=xy build. To see what effects PREFIX=blah has, the target settings can be used.