Support negation of requirements

Open

#610 opened on May 19, 2020 4 comments 0 reactions 0 assignees View on GitHub

transition

Description

If you want to build something on Windows only my current solution was: `no windows:yes`

However this causes conflicts when any other rule (e.g. C++11 requirements) adds a `no` too

Hence it would be great if negation like `!windows:no` would be supported

The current solution involves a rather clunky `conditional` and a function

This issue has not been assessed yet.