Fix semantic rules for system libraries

The issue was that the previous implementation would match any file that contains a file that ends with the same name as a given system file. For instance BDE's open source library has a file named 'bdlpcre_regex.h', which matches with 'regex.h'.

It can still match local project files that fully matches the system file names, but then again, this could potentially be an issue in the project that has such files, while including them with <> instead of "".