bpfmt was always exiting with return code 0, make it use the
exitCode recorded when reporting errors.
Also use the usage function.
Test: bpfmt -o bpfmt.go
Test: bpfmt
Test: bpfmt -h
Fixes: 113069050
Change-Id: I717d524c5f43cd36f52e33964a37324cc04c5df0
This is partially in hopes of making it generally easier to use, and
partially in hopes of specifically making it less tempting to do
bpfmt Android.bp > Android.bp
which actually would just erase the contents of Android.bp
Test: bpfmt Android.bp 2>&1 | grep usage && echo ok
Bug: 67326589
Change-Id: I41c23aca6214f27dbdf55e5931f9392c318e82ed
Make integrating with go tools easier by putting the blueprint package
files in the top level directory of the git project instead of in a
subdirectory called blueprint.
Change-Id: I35c144c5fe7ddf34e478d0c47c50b2f6c92c2a03
