diff --git a/src/main/org/apache/tools/ant/launch/Launcher.java b/src/main/org/apache/tools/ant/launch/Launcher.java
index a8d69e10e..4407d7f3f 100644
--- a/src/main/org/apache/tools/ant/launch/Launcher.java
+++ b/src/main/org/apache/tools/ant/launch/Launcher.java
@@ -36,6 +36,9 @@ public class Launcher {
     /** The Ant Home property */
     public static final String ANTHOME_PROPERTY = "ant.home";
 
+    /** The Ant Library Directory property */
+    public static final String ANTLIBDIR_PROPERTY = "ant.library.dir";
+
     /** The location of a per-user library directory */
     public static final String USER_LIBDIR = ".ant/lib";
 
@@ -138,7 +141,18 @@ public class Launcher {
         // Now try and find JAVA_HOME
         File toolsJar = Locator.getToolsJar();
 
-        URL[] systemJars = Locator.getLocationURLs(jarDir);
+        // determine ant library directory for system jars: use property
+        // or default using location of ant-launcher.jar
+        File antLibDir = null;
+        String antLibDirProperty = System.getProperty(ANTLIBDIR_PROPERTY);
+        if (antLibDirProperty != null) {
+            antLibDir = new File(antLibDirProperty);
+        }
+        if ((antLibDir == null) || ! antLibDir.exists()) {
+            antLibDir = jarDir;
+            System.setProperty(ANTLIBDIR_PROPERTY, antLibDir.getAbsolutePath());
+        }
+        URL[] systemJars = Locator.getLocationURLs(antLibDir);
 
         File userLibDir
             = new File(System.getProperty("user.home"), USER_LIBDIR);
diff --git a/src/script/ant b/src/script/ant
index 42d614431..163bbd4f5 100644
--- a/src/script/ant
+++ b/src/script/ant
@@ -14,23 +14,64 @@
 #   See the License for the specific language governing permissions and
 #   limitations under the License.
 
-# load system-wide ant configuration
-if [ -f "/etc/ant.conf" ] ; then
-  . /etc/ant.conf
-fi
+# Extract launch and ant arguments, (see details below).
+ant_exec_args=
+no_config=false
+use_jikes_default=false
+ant_exec_debug=false
+show_help=false
+for arg in "$@" ; do
+  if [ "$arg" = "--noconfig" ] ; then
+    no_config=true
+  elif [ "$arg" = "--usejikes" ] ; then
+    use_jikes_default=true
+  elif [ "$arg" = "--execdebug" ] ; then
+    ant_exec_debug=true
+  elif [ "$arg" = "--h" -o "$arg" = "--help" ] ; then
+    show_help=true
+    ant_exec_args="$ant_exec_args -h"
+  else
+    if [ "$arg" = "-h" -o "$arg" = "-help" ] ; then
+      show_help=true
+    fi
+    ant_exec_args="$ant_exec_args \"$arg\""
+  fi
+done
 
-# provide default values for people who don't use RPMs
-if [ -z "$rpm_mode" ] ; then
-  rpm_mode=false;
-fi
+# Source/default ant configuration
+if $no_config ; then
+  rpm_mode=false
+  usejikes=$use_jikes_default
+else
+  # load system-wide ant configuration
+  if [ -f "/etc/ant.conf" ] ; then
+    . /etc/ant.conf
+  fi
 
-if [ -z "$usejikes" ] ; then
-  usejikes=false;
+  # load user ant configuration
+  if [ -f "$HOME/.ant/ant.conf" ] ; then
+    . $HOME/.ant/ant.conf
+  fi
+  if [ -f "$HOME/.antrc" ] ; then
+    . "$HOME/.antrc"
+  fi
+
+  # provide default configuration values
+  if [ -z "$rpm_mode" ] ; then
+    rpm_mode=false
+  fi
+  if [ -z "$usejikes" ] ; then
+    usejikes=$use_jikes_default
+  fi
 fi
 
-# load user ant configuration
-if [ -f "$HOME/.antrc" ] ; then
-  . "$HOME/.antrc"
+# Setup Java environment in rpm mode
+if $rpm_mode ; then
+  if [ -f /usr/share/java-utils/java-functions ] ; then
+    . /usr/share/java-utils/java-functions
+    set_jvm
+    set_javacmd
+  fi
 fi
 
 # OS specific support.  $var _must_ be set to either true or false.
@@ -109,29 +150,58 @@ if [ ! -x "$JAVACMD" ] ; then
   exit 1
 fi
 
-# in rpm_mode get ant/optional/xml parser&api from JAVALIBDIR
-if $rpm_mode; then
-  JAVALIBDIR=/usr/share/java
-  for i in ant ant-optional jaxp_parser xml_apis
-  do
-    if [ -z "$LOCALCLASSPATH" ] ; then
-      LOCALCLASSPATH="$JAVALIBDIR/$i.jar"
-    else
-      LOCALCLASSPATH="$JAVALIBDIR/$i.jar:$LOCALCLASSPATH"
+# Build local classpath using just the launcher in non-rpm mode or
+# use the Jpackage helper in rpm mode with basic and default jars
+# specified in the ant.conf configuration. Because the launcher is
+# used, libraries linked in ANT_HOME will also be include, but this
+# is discouraged as it is not java-version safe. A user should
+# request optional jars and their dependencies via the OPT_JAR_LIST
+# variable
+if $rpm_mode && [ -f /usr/bin/build-classpath ] ; then
+  LOCALCLASSPATH="$(/usr/bin/build-classpath ant ant-launcher jaxp_parser_impl xml-commons-apis)"
+  # If the user requested to try to add some other jars to the classpath
+  if [ -n "$OPT_JAR_LIST" ] ; then
+    _OPTCLASSPATH="$(/usr/bin/build-classpath $OPT_JAR_LIST 2> /dev/null)"
+    if [ -n "$_OPTCLASSPATH" ] ; then 
+      LOCALCLASSPATH="$LOCALCLASSPATH:$_OPTCLASSPATH"
     fi
-  done
+  fi
 
-  # in rpm mode ant/lib is in /usr/share/java/ant
-  ANT_LIB="${JAVALIBDIR}/ant"
-fi
+  # Explicitly add javac path to classpath, assume JAVA_HOME set
+  # properly in rpm mode
+  if [ -f "$JAVA_HOME/lib/tools.jar" ] ; then
+    LOCALCLASSPATH="$LOCALCLASSPATH:$JAVA_HOME/lib/tools.jar"
+  fi
+  if [ -f "$JAVA_HOME/lib/classes.zip" ] ; then
+    LOCALCLASSPATH="$LOCALCLASSPATH:$JAVA_HOME/lib/classes.zip"
+  fi
 
-if [ -z "$LOCALCLASSPATH" ] ; then
-    LOCALCLASSPATH=$ANT_LIB/ant-launcher.jar
+  # if CLASSPATH_OVERRIDE env var is set, LOCALCLASSPATH will be
+  # user CLASSPATH first and ant-found jars after.
+  # In that case, the user CLASSPATH will override ant-found jars
+  #
+  # if CLASSPATH_OVERRIDE is not set, we'll have the normal behaviour
+  # with ant-found jars first and user CLASSPATH after
+  if [ -n "$CLASSPATH" -a -n "$CLASSPATH_OVERRIDE" ] ; then
+     # prepend local class path with class path override
+     if [ -z "$LOCALCLASSPATH" ] ; then 
+       LOCALCLASSPATH="$CLASSPATH"
+     else
+       LOCALCLASSPATH="$CLASSPATH:$LOCALCLASSPATH"
+    fi
+
+    # remove class path from launcher -lib option
+    CLASSPATH=""
+  fi
 else
-    LOCALCLASSPATH=$ANT_LIB/ant-launcher.jar:$LOCALCLASSPATH
+  # not using rpm_mode; use launcher to determine classpaths
+  if [ -z "$LOCALCLASSPATH" ] ; then
+      LOCALCLASSPATH=$ANT_LIB/ant-launcher.jar
+  else
+      LOCALCLASSPATH=$ANT_LIB/ant-launcher.jar:$LOCALCLASSPATH
+  fi
 fi
 
-
 if [ -n "$JAVA_HOME" ] ; then
   # OSX hack to make Ant work with jikes
   if $darwin ; then
@@ -153,21 +223,43 @@ fi
 # For Cygwin, switch paths to Windows format before running java
 if $cygwin; then
   ANT_HOME=`cygpath --windows "$ANT_HOME"`
+  ANT_LIB=`cygpath --windows "$ANT_LIB"`
   JAVA_HOME=`cygpath --windows "$JAVA_HOME"`
   LOCALCLASSPATH=`cygpath --path --windows "$LOCALCLASSPATH"`
   CYGHOME=`cygpath --windows "$HOME"`
 fi
 
+# Show script help if requested
+if $show_help ; then
+  echo $0 '[script options] [options] [target [target2 [target3] ..]]'
+  echo 'Script Options:'
+  echo '  --help, --h            print this message and ant help'
+  echo '  --noconfig             suppress sourcing of /etc/ant.conf,'
+  echo '                         $HOME/.ant/ant.conf, and $HOME/.antrc'
+  echo '                         configuration files'
+  echo '  --usejikes             enable use of jikes by default, unless'
+  echo '                         set explicitly in configuration files'
+  echo '  --execdebug            print ant exec line generated by this'
+  echo '                         launch script'
+  echo '  '
+fi
+
+# Execute ant using eval/exec to preserve spaces in paths,
+# java options, and ant args
+ant_sys_opts=
 if [ -n "$CYGHOME" ]; then
   if [ -n "$JIKESPATH" ]; then
-    exec "$JAVACMD" $ANT_OPTS -classpath "$LOCALCLASSPATH" -Dant.home="${ANT_HOME}" -Djikes.class.path="$JIKESPATH" -Dcygwin.user.home="$CYGHOME" org.apache.tools.ant.launch.Launcher $ANT_ARGS -lib "$CLASSPATH" "$@"
+    ant_sys_opts="-Djikes.class.path=\"$JIKESPATH\" -Dcygwin.user.home=\"$CYGHOME\""
   else
-    exec "$JAVACMD" $ANT_OPTS -classpath "$LOCALCLASSPATH" -Dant.home="${ANT_HOME}" -Dcygwin.user.home="$CYGHOME" org.apache.tools.ant.launch.Launcher $ANT_ARGS -lib "$CLASSPATH" "$@"
+    ant_sys_opts="-Dcygwin.user.home=\"$CYGHOME\""
   fi
 else
   if [ -n "$JIKESPATH" ]; then
-    exec "$JAVACMD" $ANT_OPTS -classpath "$LOCALCLASSPATH" -Dant.home="${ANT_HOME}" -Djikes.class.path="$JIKESPATH" org.apache.tools.ant.launch.Launcher $ANT_ARGS -lib "$CLASSPATH" "$@"
-  else
-    exec "$JAVACMD" $ANT_OPTS -classpath "$LOCALCLASSPATH" -Dant.home="${ANT_HOME}" org.apache.tools.ant.launch.Launcher $ANT_ARGS -lib "$CLASSPATH" "$@"
+    ant_sys_opts="-Djikes.class.path=\"$JIKESPATH\""
   fi
 fi
+ant_exec_command="exec \"$JAVACMD\" $ANT_OPTS -classpath \"$LOCALCLASSPATH\" -Dant.home=\"$ANT_HOME\" -Dant.library.dir=\"$ANT_LIB\" $ant_sys_opts org.apache.tools.ant.launch.Launcher $ANT_ARGS -lib \"$CLASSPATH\" $ant_exec_args"
+if $ant_exec_debug ; then
+    echo $ant_exec_command
+fi
+eval $ant_exec_command