The patch updates the MSVC ToolChain for the changes made in Visual Studio 2017 (https://blogs.msdn.microsoft.com/vcblog/2016/10/07/compiler-tools-layout-in-visual-studio-15/).
Other notable changes:
- Path handling code has been centralised to make potential future changes less painful.
- A compiler error is emitted if the driver is unable to locate a usable MSVC toolchain. (Previously it'd fail with a cryptic error such as "link.exe is not executable")
- Support for the new Setup Config Server API has been added, albeit block commented out with a preprocessor conditional. This can probably be re-evaluated when the API is officially released (it's currently at the RC stage), but it's left in to make it easy for anyone familiar with the API to give it a go with Clang.
Patch by Hamza Sood.