Build script: Restruct Scons 3.0.0 compatibility patch to already released Mesa versions. Patch is picked for 17.2.3 release and landed in 17.2 branch head.
Build script: Restruct Scons 3.0.0 compatibility patch to already released Mesa versions.
Patch is picked for 17.2.3 release and landed in 17.2 branch head.

pal1000/mesa-dist-win,pal1000/mesa-dist-win