If you cannot afford to use Boost, then there is a very minimal library that I implemented which simply acts as a wrapper around each operating system's native guid implementation. It should work on Windows (using CoCreateGuid), Linux (using libuuid), MacOS (using CFUUID), iOS (also using CFUUID), and Android (using JNI calls to java.util.UUID). The guid generation function has a different implementation on each system but there is single generic implementation for comparing, stringifying, and parsing.
It is MIT licensed and available on GitHub:
https://github.com/graeme-hill/crossguid
http://graemehill.ca/minimalist-cross-platform-uuid-guid-generation-in-c++/