diff --git a/build.bat b/build.bat
index 5a7f60a..e2008fa 100644
--- a/build.bat
+++ b/build.bat
@@ -38,7 +38,7 @@
 set ANT_ARGS=-buildfile build.xml -logger org.apache.tools.ant.NoBannerLogger
 
 rem raise stack size ...
-set ANT_OPTS=-Xmx128m -mx128m
+set ANT_OPTS=-Xss512k -Xmx128m -mx128m
 
 set SAVE_ANT_HOME=%ANT_HOME%
 set ANT_HOME=
diff --git a/build.sh b/build.sh
index 61eb584..722224a 100755
--- a/build.sh
+++ b/build.sh
@@ -38,7 +38,7 @@
 ANT_ARGS="-Dant.regexp.regexpimpl=org.apache.tools.ant.util.regexp.JakartaOroRegexp $ANT_ARGS"
 
 # raise heap/stack size...
-ANT_OPTS="-Xmx128m -mx128m"
+ANT_OPTS="-Xss512k -Xmx128m -mx128m"
 
 # set classpath
 CLASSPATH=./lib