Merge pull request ruby#47 from jhawthorn/patch-1

Recommend installing libcapstone in README

README.md

@@ -39,6 +39,8 @@ cd yjit
 
 The YJIT `ruby` binary can be built with either GCC or Clang. We recommend enabling debug symbols so that assertions are enabled during development as this makes debugging easier. Enabling debug mode will also make it possible for you to disassemble code generated by YJIT, and get access to stat counters. More detailed build instructions are provided in the [Ruby README](https://github.com/ruby/ruby#how-to-compile-and-install).
 
+To support disassembly of the generated code, `libcapstone` is also required (`brew install capstone` on MacOS, `sudo apt-get install -y libcapstone-dev` on Ubuntu/Debian).
+
 ```
 ./autogen.sh
 ./configure cppflags=-DRUBY_DEBUG --prefix=$HOME/.rubies/ruby-yjit