Mention that setjmp/longjmp are not yet supported.

README.md

@@ -35,8 +35,10 @@ in the install directory.
 ## Notable Limitations
 
 This repository does not yet support C++ exceptions. C++ code is
-supported only with -fno-exceptions for now. Work on support for
-[exception handling] is underway at the language level.
+supported only with -fno-exceptions for now. Similarly, there is not
+yet support for setjmp/longjmp. Work on support for [exception handling] 
+s underway at the language level which will support both of these
+features.
 
 [exception handling]: https://github.com/WebAssembly/exception-handling/