At present patman sets the python path on startup so that it can access
the libraries it needs. If we convert to use absolute imports this is not
necessary.

Move patman to use absolute imports. This requires changes in tools which
use the patman libraries (which is most of them).

Signed-off-by: Simon Glass <sjg@chromium.org>

At present buildman does not write its own output files (err, done, the
environment) when using -w. However this is useful for when the build is
run with -s to check it.

In fact ProduceResultSummary() reads the result from those files rather
than using the 'result' info directly. So ProcessResult() does not work
with -w at present. It does not print any output.

Fix this by writing output files even when -w is used.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present the environment used by U-Boot is written to the 'env'
directory. This is fine when the output directory is not the same as the
source directory, but when it is (as with -w) it conflicts with the source
directory of the same name.

Rename 'env' to 'out-env' to fix this.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present buildman defaults to running 'mrproper' on every thread before
it starts building commits for each board. This can add a delay of about 5
seconds to the start of the process, since the tools and other invariants
must be rebuilt.

In particular, a build without '-b', to build current source, runs much
slower without -I, since any existing build is removed, thus losing the
possibility of an incremental build.

Partly this behaviour was to avoid strange build-system problems caused by
running 'make defconfig' for one board and then one with a different
architecture. But these problems were fixed quite a while ago.

The -I option (which disabled mrproper) was introduced four years ago and
does not seem to cause any problems with builds.

So make -I the default and deprecate the option. To allow use of
'mrproper', add a new -m flag.

Signed-off-by: Simon Glass <sjg@chromium.org>

It is useful to run a simple build and put all the output in a single
directory. Add a -w option to support this.

Signed-off-by: Simon Glass <sjg@chromium.org>

This class has a few more members now. Add documentation for them and fix
a nit in the 'commits' comment.

Signed-off-by: Simon Glass <sjg@chromium.org>

Convert buildman to Python 3 and make it use that, to meet the 2020
deadline.

Signed-off-by: Simon Glass <sjg@chromium.org>

Sometimes it is useful to see the environment that was used to build
U-Boot. Write this out to a file in the build directory.

Signed-off-by: Simon Glass <sjg@chromium.org>

Add a -O option which allows building with clang.

Signed-off-by: Simon Glass <sjg@chromium.org>

The 'done' files created by buildman may end up being empty if buildman
runs out of disk space while writing them. This error is then persistent,
since even if disk space is reclaimed and the build retries, the empty
file causes an exception in the builder thread.

Deal with this silently by doing a rebuild.

Signed-off-by: Simon Glass <sjg@chromium.org>