"At ["Google"] we needed a replacement for getopt() that was both simpler to use and more powerful ...", according to [http://google-code-updates.blogspot.com/2007/03/four-google-open-source-tools-on-google.html this] description of a few tools released to the public in spring 2007. Another one automates production of manual pages from a gflags description.
"["Option parsing tools"] describes alternatives.