Update in .bashrc to be OSX compliant

dotfiles/bash/bashrc

@@ -6,7 +6,13 @@
 
 # This monstrosity returns the directory of the .bashrc from it's symlinked source so we can
 # call script files correctly.
+
+if [[ "$OSTYPE" == "linux-gnu" ]]; then
   symlink_dir=$(cd "$( dirname "`readlink -f ${BASH_SOURCE[0]}`" )" && pwd)
+else
+  # OS X is not a fan of `readlink -f`
+  symlink_dir=$(cd "$( dirname "`readlink ${BASH_SOURCE[0]}`" )" && pwd)
+fi
 
 # Useful global functions
 alias cgen=$symlink_dir/scripts/cgen.sh