Seeing as I consider Qt to be a particularly badly designed C++ library, this speaks volumes about how cumbersome some C APIs are to use. Not that there is any real alternative for a cross-platform UI toolkit.
Python & QT could be an option, but the whitespace is annoying (I shudder to think what Linus thinks of it) and in general, I prefer using Go over Python, but the creators have said they will not put any resources into developing official UI bindings, so any efforts are purely third-party.