faa8f68943 Replace boost::variant with std::variant (MarcoFalke)
Pull request description:
Now that we can use std::variant from the vanilla standard library, drop the third-party boost variant dependency
ACKs for top commit:
fjahr:
Code review ACK faa8f68943
fanquake:
ACK faa8f68943
Tree-SHA512: 6e3aecd33b00c2e31a763f999247944d5b2ce5e3018f1965c516c1000cd08ff6703a8d50fb0be64883153da2925ae72986b8a6b96586db74057bd05d6f4986e6