Compiling Mono (and PlayScript) on OSX Mountain Lion (10.8)

Quick update/note: Zynga has pulled the source for PlayScript, and no one has taken it up. Safe to assume it’s a dead project.

A while back, Zynga employees demonstrated a project they are working on called PlayScript, an implementation of AS3 and an ASNext wish-list language they named PlayScript on the Mono Platform. In order to play with it, it’s probably best to compile your own copy, since any binaries they post will quickly get out of date. Wanting to play around with it on my iPhone, I took a stab at compiling the Mono Project on OSX, for use in Xamarin Studio. I used a copy of PlayScript-mono for this post, but these instruction should really apply to any fork of Mono (I think).

The OSX compile instruction page on is a bit hard to follow if you are new to this stuff, so I thought I’d write up some more detailed instructions in the hope it would save someone some time.

First, the prerequisites. You’ll need Xcode, and the command line tools. Grab Xcode out of the Mac App Store, and run it. Then go to Preferences under the Xcode menu, then the Downloads Tab/button/icon (organizationally, it’s tab, but it looks like a button with an icon). In there, you should install “Command Line Tools”. This contains some of the stuff you’ll need to build Mono on OSX.

The build instructions on say you’ll need a version of mono installed before you can compile. I had Xamarin and Unity3D installed before I tried to build, and one of them seemed to cover my bases.

There are a couple of prereqs still missing. From various sources, it looks like the make and autoconf tools used to be included with Xcode’s command line package, but they aren’t anymore in OSX 10.8 (Mtn Lion). There are a couple of ways to install them, including building them yourself, but the easiest way I found is to use Brew. Installing Brew is easy enough – copy the ruby command from the brew website, and run it in a terminal.

I always recommend going to the primary source for the correct install method on these kinds of things, so go there, install, and then come back.

Next, use brew to install automake, autoconf, and libtool. You don’t need “sudo” – but don’t worry, brew will complain if you forget. You’ll get a message about libtool being prefixed with a g to avoid conflicts – this didn’t seem to have any unwanted effect for building Mono.

brew install autoconf libtool automake

Note: I had trouble with brew install and libtool on a new mac while writing this post. I didn’t have this problem when I built it on an older iMac. I’m not sure what caused it, but if you get any errors during the brew step (mine was about linking libtool) you can type “brew doctor” in the build directory, and it’ll give you some pointers. My specific problem was that /usr/local/lib wasn’t owned by my user account. The brew suggestion was to “chown” that dir, and rerun the link command for libtool (the step that failed during install), so this was the command I used to fix my brew libtool problem:

sudo chown $USER /usr/local/lib
brew link libtool

There were some other notes about rearranging things in your path for git, etc., but I didn’t bother with any of that.

Now we are ready to compile Mono. The first thing you need to do is download a copy of the Mono source from somewhere. A mainline mono archive or SVN checkout would work, or you could clone a local copy of PlayScript-mono from GitHub, then go inside the folder, which is what I did:

git clone
cd playscript-mono

Now we are up to the configure stage, which is where you will start to run into trouble if you don’t have the proper prerequisites setup. The instructions on mono-project say you can use ./configure from a tar, but I wasn’t able to get that to work from either git or tarball. ./ seemed to work from both sources though. Note: the prefix flag is where Mono will be installed when you run “make install” and unless you know what you are doing, you probably don’t want to leave that as the default value. Here’s the bolded warning from mono-project, “It is strongly advised not to install Mono from source in /usr, /usr/local or any other “standard” directories unless you know what you are doing.” I put mine in a directory matching the repo name I’m building from my user directory.

./ –prefix=/users/{kevin}/mono-playscript –enable-nls=no
make install

This can take a LONG time!