compiling the kernel in another directory, and using VPATH

[Robert P. J. Day]

  i asked about this once upon a time, and i finally got around to trying 
to set it up.  what i want to do is take a cleaned, pristine kernel source
directory, and configure and build it in a separate work directory so that 
the source directory remains absolutely untouched.  ideally, i'd like to 
write-protect that entire directory, and have all of the results 
(generated header files, object files, etc.) placed in a parallel work
directory, so multiple developers can be configuring and building a kernel 
image independently without stepping on each others' toes, but working off 
of the same kernel source directory, of course.

  i've been reading up on VPATH but i'm not convinced it's the exact 
solution.  from what i read, VPATH is great if i want to identify 
alternate locations for the occasional pre-requisite files.  but as you 
can see, i want the entire source directory to be elsewhere.

  this whole process seems like such an obvious project that i'm assuming 
*someone*'s done it before.  to recap, for those who've done lots of 
kernel builds before, i want to do 

  $ make mrproper

in the source directory, to remove *every* trace of a previous build, as 
the starting point for the kernel source tree.

  each developer will be responsible for setting up their own work
directory, with their own .config file and so on.  the kernel source
directory will be world-readable, but no one should generate even a single
file in that directory -- all results should be dumped into each
developers' personal work directory.

  am i asking a bit too much here?  this would be tres cool if i could 
pull it off.

rday