custom extension for make/SourceRevision.gmk

[Christian Thalinger]

Here at Twitter our OpenJDK clone lives in a GIT repository and we would like to use the source-revision feature of the release file.

I have all the custom extension logic in place to create the revision tracker:

$ cat build/macosx-x86_64-normal-server-release/support/src-rev/source-revision-tracker 
.:ea60d3b1efc0

but the way make/SourceRevision.gmk is structured (the custom extensions is included at the top of the file) always triggers the warning:

$ make
Building target 'default (exploded-image)' in configuration 'macosx-x86_64-normal-server-release'
Warning: No mercurial configuration present and no .src-rev
Finished building target 'default (exploded-image)' in configuration 'macosx-x86_64-normal-server-release'

Is there a way so silence the warning without restructuring the upstream file?  And if no, can we change it so it works?