diff --git a/README b/README
index 5271e31cf..c2a2e4502 100644
--- a/README
+++ b/README
@@ -12,7 +12,7 @@ Make sure that /opt/local/bin (macport tools) arrives first in your PATH env var
 
 Once xcode and macports are installed, open a terminal and install the required build-time tools with:
 
-	$ sudo port install coreutils automake autoconf libtool intltool wget pkgconfig cmake gmake yasm grep doxygen ImageMagick optipng
+	$ sudo port install coreutils automake autoconf libtool intltool wget pkgconfig cmake gmake yasm grep doxygen ImageMagick optipng antlr3
 
 
 Install gas-preprosessor.pl  (http://github.com/yuvi/gas-preprocessor/ ) to be copied into /opt/local/bin :