[Ltib] Issue when changing toolchains in a build

[Peter Barada]

Stuart,

If I have a build where the kernel source is needed to build another
module, (or some other package source is needed for another package to
build), then the package is built and the source/object files are in
rpm/BUILD.  If I then do "./ltib -c" and change the toolchain, LTIB
properly de-installs all the packages, and then builds the packages
again using the new toolchain, including the source that was left behind
from the previous build.

So far so good, but if the new toolchain default (on ARM for example)
causes incompatible object files (i.e. using hard vs soft float ABI on
ARM), then the package source that was previously built will fail to
build/link due to the incompatibility.

I think the right way to fix this is to execute a "distclean" on package
source that exist, triggered by ${LTIB_FULL_REBUILD} before rebuilding,
but so far I haven't quite figured out the path to get this to happen. 
I'm more than happy to tackle it but need a pointer that makes the code
flow clear.

Thanks in advance!

-- 
Peter Barada
address@hidden