Add linter hints for issues with OSX configuration in CBC

[h-vetinari]

Linter portion of #1927, but also adding linter hints for warnings from #1889, which were so far only visible when running smithy locally.

[maresb]

I was pretty confused about the c_stdlib_version below the current global baseline warning I received here.

After some investigation I realized that it was coming from this file. (It would have been helpful to indicate the filename recipe/conda_build_config.yaml.) I created that file according to this announcement and then forgot about it.

My confusion was because I don't have the bigger picture of what's going on, and when I created conda_build_config.yaml I was blindly following the announcement without fully realizing that I was pinning the c_stdlib_version which might need to be updated in the future. In my case it seemed to work to simply delete the entry from conda_build_config.yaml. Should this be mentioned as another possible resolution? (Also, I hope this was the correct action in my case?)

[h-vetinari]

I was pretty confused about the c_stdlib_version below the current global baseline warning I received here.

Sorry about that...

In my case it seemed to work to simply delete the entry from conda_build_config.yaml. Should this be mentioned as another possible resolution?

PRs to improve the warning messages here (or documentation), so that they would have been more understandable to you, would be greatly appreciated!

Also, I hope this was the correct action in my case?

Yes, deleting a pin for c_stdlib_version <10.13 is completely fine.