Merge pull request #13 from snd/snd-improve-osx-install

update readline osx specific install instructions

README.md

@@ -23,10 +23,28 @@ Before starting with it, make sure you have libgmp-dev installed otherwise ghc w
 
 [solc](https://www.npmjs.com/package/solc) is another echidna dependency not handled via stack.
 It is technically optional, but working with solidity source will fail without it.
+Run `npm install -g solc` to install it.
 
-Once solc is installed, installing stack and running `stack upgrade; stack setup; stack install` from inside the directory should be all that's needed.
+Once solc is installed, installing stack (`brew install stack`) and running
 
-If you have weird problems involving `readline` on MacOS, try `brew install readline; brew link readline; stack install readline --extra-include-dirs=/usr/local/opt/readline/include --extra-lib-dirs=/usr/local/opt/readline/lib; stack install`.
+```
+stack upgrade
+stack setup
+stack install
+```
+
+from inside the echidna directory should be all that's needed.
+
+If you have weird problems involving `readline` on MacOS, try:
+
+```
+brew install readline
+brew link readline --force
+export LDFLAGS=-L/usr/local/opt/readline/lib
+export CPPFLAGS=-I/usr/local/opt/readline/include
+stack install readline --extra-include-dirs=/usr/local/opt/readline/include --extra-lib-dirs=/usr/local/opt/readline/lib
+stack install
+```
 
 Notably, if you are using stack, `stack ghci` will set up a REPL with all functions in scope.
 This can be quite useful for playing around with the library.