mozilla/rust — pull request #14218 by kaseyc (2014-05-15 03:28:26+00:00)
Title: Add cfg for version based conditional compilation

Fixes #3795

This PR implements a cfg that conditionally includes code based on the current version of the Rust compiler.
It uses the syntax proposed in #3795, namely #[cfg(rust_version="X")].
It accepts the operators <, <=, >, >=, != (just for completeness), and checks for equality if no operator is specified.