Normalize LLVM_ROOT when writing sanity file

[xanzarx]

Visual Studio Code CMakeTools extension cleans cache when the editor opens in Windows. Possible root cause is different LLVM root paths string case in santiy.txt:

• For startup it produces path starting with 'c:' e.g c:\projects\emscripten\upstream\bin
• For regular cmake configuration or build it produces path starting with 'C:' e.g C:\projects\emscripten\upstream\bin
  This leads to rebuilding cache every time the editor is launched, which is a bit frustrating
  Link to similar issue

For windows path to folders is case independent anyways, so possible fix is just put lowercase string to sainty.txt for Windows.

[sbc100]

I'd like to understand this issue a little more before landing this. How/where/why is VSCode settings the llvm root?

[sbc100]

Is EM_CONFIG being set somewhere perhaps?

[xanzarx]

As it turns out running commands with drive letter in different case in windows terminal application will lead change sanity.txt (and cache rebuild)

C:\Projects\test>C:\projects\emscripten\upstream\emscripten\em++ main.cpp
sanity.txt:

3.1.59|C:/Projects/emscripten/upstream/bin

C:\Projects\test>c:\projects\emscripten\upstream\emscripten\em++ main.cpp
sanity.txt:

3.1.59|c:/Projects/emscripten/upstream/bin

For not it seems the issue was not caused (at least directly) by interaction with VS Code or CMake tools plugin for VSCode

[sbc100]

As it turns out running commands with drive letter in different case in windows terminal application will lead change sanity.txt (and cache rebuild)

C:\Projects\test>C:\projects\emscripten\upstream\emscripten\em++ main.cpp sanity.txt:

3.1.59|C:/Projects/emscripten/upstream/bin

C:\Projects\test>c:\projects\emscripten\upstream\emscripten\em++ main.cpp sanity.txt:

3.1.59|c:/Projects/emscripten/upstream/bin

For not it seems the issue was not caused (at least directly) by interaction with VS Code or CMake tools plugin for VSCode

Interesting! Thanks for the repro case. I wonder if we can make that into a test case? Maybe not worth it..