You are here trying to use snmalloc with LLVM_INTEGRATED_CRT_ALLOC on Windows but facing issue a fatal error:

fatal error: snmalloc/snmmlloc.h: No such file or directory

If possible please share your cmake command.
correct cmake as per me would be

✅ Correct CMake Command

cmake -G "Visual Studio 17 2022" -A x64 -DLLVM_INTEGRATED_CRT_ALLOC="D:\git\snmalloc" <other-cmake-options>

Try a Clean Build

Delete CMakeCache.txt and CMakeFiles before retrying:

1. rm -rf CMakeCache.txt CMakeFiles CopyEdit
   

Enable Verbose Output to Debug

cmake --trace-expand
cmake --debug-output
make VERBOSE=1

Also, you can check the CMakeCache.txt

LLVM_INTEGRATED_CRT_ALLOC:PATH=D:/git/snmalloc

This line should be present

I will also suggest if possible please start using wsl on windows for Linux build.