Issue Description:

1. Create an SPM library.

2. Give the library a minimum platform version (such as macOS 10.13).

3. Create an SPM executable, using the library as a dependency.

4. Build the executable project.

You'll get an error that looks something like this:

error: the product 'Dependency' requires minimum platform version 10.13 for macos platform

This error can be confusing, since it doesn't have to do with your current platform version. To fix it, you have to set the minimum platform version of the executable. It would make more sense if the error said something like this:

error: the executable 'Executable' has a minimum platform version lower than macos 10.13, which is required by the product 'Dependency'