diff --git a/build.sh b/build.sh
index 2b1bc03a5..63e2ea859 100755
--- a/build.sh
+++ b/build.sh
@@ -55,6 +55,8 @@ export CLASSPATH
 
 if [ "$REALANTHOME" != "" ] ; then
   ANT_INSTALL="-Dant.install=$REALANTHOME"
+else
+  ANT_INSTALL="-emacs"
 fi
 
 bootstrap/bin/ant -emacs "$ANT_INSTALL" $*