Optimise conditional compiles & package dependencies

[thompson-tomo]

No description provided.

[mythz]

Thanks for the big PR! Can you also approve the Contributor License Agreement so we can look at merging this, thanks.

[mythz]

We don't want to mix whitespace changes with other code changes in the same PR which makes it a huge PR for us to inititally review and and for others later when looking through the code base commit history. If you can remove the whitespace changes we can look at accepting the build symbol changes separately.

For widespread whitespace changes like this we'll look at running a tool like tool like dotnet format ideally from a GitHub action.