Buildscript: - Typo fixes; - Better code segmentation; - Major style improvement; - Allow MSVC 2017 toolset build hack. Removed with d62bec5, now is an opt-in.
Buildscript:
- Typo fixes;
- Better code segmentation;
- Major style improvement;
- Allow MSVC 2017 toolset build hack. Removed with d62bec5, now is an opt-in.

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