Add 64bit SWT to Mac SDK build.

Change-Id: Ie30153644733d5a22453eea2c66551e4aaa03316
diff --git a/build/sdk-darwin-x86.atree b/build/sdk-darwin-x86.atree
index 19be137..120fff0 100644
--- a/build/sdk-darwin-x86.atree
+++ b/build/sdk-darwin-x86.atree
@@ -3,6 +3,7 @@
 
 # swt
 prebuilt/darwin-x86/swt/swt.jar tools/lib/x86/swt.jar
+prebuilt/darwin-x86_64/swt/swt.jar tools/lib/x86_64/swt.jar
 
 
 # JetCreator (only available on mac/windows)