Add Shell Execution Extensions to Context

[AristurtleDev]

Adds extension methods for FrostingContext to help with executing shell commands per platform

[harry-cpp]

Just do:

private static readonly ProcessSettings _processSettings = new();

[AristurtleDev]

Done in 99399d0

[harry-cpp]

Feel free to use the => thingy here if you want.

[AristurtleDev]

Done in 99399d0

[harry-cpp]

Pass env variables in a separate function SetShellEnvVariables(parms string[] env)

[AristurtleDev]

Done in 23d2fc1

From our previous discussion, the export keyword is in fact required. Without it, the environment variables do not stay set if the command executes something that in turn executes something else. So the export is required for the entire run of the process.

[AristurtleDev]

Additionally, I was not able to find any decent way of doing space character escapes in the command. The problem comes in situations where you want to set an environment variable such as

context.SetShellEnvironmentVariables("CFLAGS", $"-w -arch arm64 -I{dependencyDir}/include");

The space escapes would need to be set for the path in the -I flag, however you would need to differentiate between what is a path and what isn't, such as the -w -arch arm64 part. Otherwise, you end up with a sanitized environment variable such as CFLAGS="-w\ -arch\ arm64\ -i/path/to\ some/directory/include;" which fails to run.

Open to suggestions on this if still needed

[harry-cpp]

You are supposed to set it to either:

CFLAGS=-w\ -arch\ arm64\ -i/path/to\ some/directory/include;

or

CFLAGS="-w -arch arm64 -i/path/to some/directory/include";