I need to determine the type of OS the PHP server is running on. By type, I mean strings like "windows" or "linux", not "wince", "winnt" etc.
So far, I have to leads: PHP_OS and uname(), the later being more reliable than the earlier (PHP_OS says what OS PHP was built on - according to documentation).
It's important to know that no non-Windows OS string is going to contain the text "win", and no non-OSX OS string is going to contain the word "darwin", and so on. Detecting the OS is easy.