Document that XCode 3.1.4 is required.

That way, we can rely on having gcc 4.2.1, whereas older
versions of XCode had 4.0.1 or older.

Bug: 4445289
Change-Id: I22ca90e9a9ab59efa2b8430317036a949848c483
diff --git a/src/source/initializing.md b/src/source/initializing.md
index e15df10..08cc5eb 100644
--- a/src/source/initializing.md
+++ b/src/source/initializing.md
@@ -130,7 +130,9 @@
 
 ## Installing required packages ##
 
-- Install XCode from [the Apple developer site](http://developer.apple.com/). We recommend version 3.0 or newer.  If you are not already registered as an Apple developer, you will have to create an Apple ID in order to download.
+- Install XCode from [the Apple developer site](http://developer.apple.com/).
+We recommend version 3.1.4 or newer. If you are not already registered as an
+Apple developer, you will have to create an Apple ID in order to download.
 
 - Install MacPorts from [macports.org](http://www.macports.org/install.php).