Detect and handle USE flags mismatch properly

[hikalium]

Created an issue from the comment:

          I took this as a temporary workaround. Since there may be a case where a USE flag mismatch would cause a surprising result, I'd like at least some sort of a warning message to be emitted. Is there a new issue to properly handle this?

Originally posted by @HidenoriKobayashi in https://github.com/google/lium/pull/153#pullrequestreview-1740931881

[mhiramat]

The force option does not consider the mismatch, so there still be issue when installing the mismatched package.