readme: add a note explaining
@@ -87,6 +87,8 @@ The build script probes for `python --version` and `python2 --version` and uses
- As an alternative to Apple's XCode LLVM, install LLVM via `brew install llvm` or `brew install llvm` and then set `PATH`, `CPPFLAGS`, and `LDFLAGS` like instructed.
+ Note that if these environment variables are not set, [bindgen](https://github.com/rust-lang/rust-bindgen) most likely uses to the wrong `libclang.dylib`, causing spurious compilation errors (see #228).
+
### Windows
- Have the latest versions of `git` and Rust ready.
