Dont run if not on darwin

prepend /opt/local/{bin,sbin} to the path

modules/macports/init.zsh

@@ -5,6 +5,10 @@
 #   Matt Cable <wozz@wookie.net>
 #
 
+if [[ "$OSTYPE" != darwin* ]]; then
+    return 1
+fi
+
 # Aliases
 alias pc="sudo port clean --all installed"
 alias pi="sudo port install $1"
@@ -13,3 +17,7 @@ alias puni="sudo port uninstall inactive"
 alias puo="sudo port upgrade outdated"
 alias pup="psu && puo"
 
+path=(
+    /opt/local/{bin,sbin}
+$path
+)