Wildcards are not case-sensitive on Linux

The wildcard filter

Application {
    Depends { name: "cpp" }
    name: "test"
    files: "**/*.S"
}

matches even .s files on Linux. That is a problem if there are both .S and .s files in the same source tree as those have a different meanings and the cpp module has different rules for both. Wildcard filters should always be case-sensitive.