matc error in Windows build on latest main

[patrikhuber]

Describe the bug
When I compile the filament CMake target on Windows using Visual Studio, I get a bunch of matc.exe errors during the build:

This happens when matc is invoked during the build, and trying to compile some materials:

[53/172] Compiling material C:/Users/PatrikHuber/Projects/Dependencies/filament-github-source/filament/src/materials/bloom/bloomDownsample2x.mat
FAILED: filament/generated/material/bloomDownsample2x.filamat C:/Users/PatrikHuber/Projects/Dependencies/filament-github-source/out/build/x64-debug/filament/generated/material/bloomDownsample2x.filamat 
C:\WINDOWS\system32\cmd.exe /C "cd /D C:\Users\PatrikHuber\Projects\Dependencies\filament-github-source\out\build\x64-debug\filament && C:\Users\PatrikHuber\Projects\Dependencies\filament-github-source\out\build\x64-debug\tools\matc\matc.exe -a opengl -a vulkan -p desktop -d -g -o C:/Users/PatrikHuber/Projects/Dependencies/filament-github-source/out/build/x64-debug/filament/generated/material/bloomDownsample2x.filamat C:/Users/PatrikHuber/Projects/Dependencies/filament-github-source/filament/src/materials/bloom/bloomDownsample2x.mat"
[54/172] Compiling material C:/Users/PatrikHuber/Projects/Dependencies/filament-github-source/filament/src/materials/colorGrading/colorGrading.mat
FAILED: filament/generated/material/colorGrading.filamat C:/Users/PatrikHuber/Projects/Dependencies/filament-github-source/out/build/x64-debug/filament/generated/material/colorGrading.filamat 
C:\WINDOWS\system32\cmd.exe /C "cd /D C:\Users\PatrikHuber\Projects\Dependencies\filament-github-source\out\build\x64-debug\filament && C:\Users\PatrikHuber\Projects\Dependencies\filament-github-source\out\build\x64-debug\tools\matc\matc.exe -a opengl -a vulkan -p desktop -d -g -o C:/Users/PatrikHuber/Projects/Dependencies/filament-github-source/out/build/x64-debug/filament/generated/material/colorGrading.filamat C:/Users/PatrikHuber/Projects/Dependencies/filament-github-source/filament/src/materials/colorGrading/colorGrading.mat"
ninja: build stopped: subcommand failed.

I don't think it happens with all the materials, some look like the "Compiling material" command doesn't cause the error.

When I go back to Filament tag v1.63.0, then it works. So I think there's a commit between 1.63.0 and main that messed this up.

To Reproduce
See above - clone Filament repo, open in Visual Studio 2022, compile "filament" target, observe the error.

Expected behavior
matc should run successfully.

Screenshots
See above.

Logs
See above.

Desktop (please complete the following information):

• OS: Windows
• GPU: n/a (NVIDIA)
• Backend: n/a

[pixelflinger]

This should be fixed as of last night.

[patrikhuber]

I can confirm this is fixed in latest main, thanks.