MILESTONE and BUILD_NUMBER with new build system

[Henri Gomez]

OpenJDK reports like this :

openjdk version "1.8.0-internal"
OpenJDK Runtime Environment (build 1.8.0-internal-myuser_2012_09_24_15_47-b00)
OpenJDK Server VM (build 24.0-b21, mixed mode)

With old build system I used to set MILESTONE and BUILD_NUMBER env
vars to have JDK reports like this :

openjdk version "1.8.0-b56"
OpenJDK Runtime Environment (build 1.8.0-b56-20120918)
OpenJDK 64-Bit Server VM (build 24.0-b21, mixed mode)

How did we set them now with new build system ?

Cheers