This adds a few known limitations around threading to the README and suggests the users to look into GitHub issues to learn more.
has no access to most platform-specific APIs or FFI. A few APIs have been
implemented (such as printing to stdout) but most have not: for example, Miri
currently does not support SIMD or networking.
+* Threading support is not finished yet. E.g. weak memory effects are not
+ emulated and spin loops (without syscalls) just loop forever. There's no
+ threading support on Windows.
+
+Consider looking into GitHub isues for more information about the limitations.
[rust]: https://www.rust-lang.org/
[mir]: https://github.com/rust-lang/rfcs/blob/master/text/1211-mir.md