Update not yet supported section of the readme

Author: bjorn3

Readme.md

@@ -53,7 +53,8 @@ configuration options.
 
 * Inline assembly ([no cranelift support](https://github.com/bytecodealliance/wasmtime/issues/1041))
     * On UNIX there is support for invoking an external assembler for `global_asm!` and `asm!`.
-* SIMD ([tracked here](https://github.com/bjorn3/rustc_codegen_cranelift/issues/171), some basic things work)
+* SIMD ([tracked here](https://github.com/bjorn3/rustc_codegen_cranelift/issues/171), `std::simd` fully works, `std::arch` is partially supported)
+* Unwinding on panics ([no cranelift support](https://github.com/bytecodealliance/wasmtime/issues/1677), `-Cpanic=abort` is enabled by default)
 
 ## License