resurrecting Bud and Rebuild

[BCS]

Derek Parnell wrote:
> 
> 
> I totally agree with Gregor. The -J switch might give us a hint that the
> files /on the command line/ must be recompiled, but it still doesn't make
> it easier to find out what other files are needed in the application. One
> purpose of Bud, and I assume Rebuild, is to allow the coder to just enter
> one name on the command line and get all the other required files magically
> included in the compilation process. The alternative is to require the
> coder to maintain makefiles and/or type every required file onto the
> command line.
> 


All that build tool needs is to maintain a list of *everything* that was 
looked at. The first time around (clean build) everything has to be 
built anyway so you just walk around building things. until everything 
is built, then link every .o you just built. After that you look at the 
list of things that you used last time, and if any of them change you 
rebuild everything that got you there.

the only thing hindering this I can think of is an apparent desirer to 
have the build process be state-less (it isn't now as we leave around 
lots of .o files).