Feature request: Add custom compiler flags to CMake generated project
The new CMake generation is great! It's very tastefully done (toochain file, presets, simple CMakeLists.txt, etc).
My request: I want to add some additional compiler flags (like `-Wconversion`) to my project.
In the top CMakeLists.txt I did:
```cmake
target_compile_options(${CMAKE_PROJECT_NAME} PRIVATE
"-Wconversion"
)
```
The problem is that it applies to the HAL as well, generating an endless stream of errors.
I could create a new cmake target for my own functions, but I wish the generated CMake template would support this out of the box.
Regards,
Gabriel
