diff --git a/WHATSNEW b/WHATSNEW
index ef1917752..2644bdd46 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -84,6 +84,11 @@ Fixed bugs:
  * Length task did not process nonexistent Resources even though these might
    conceivably still carry file length information.  Bugzilla report 45271.
 
+ * <javac>'s includeJavaRuntime="false" should work for gcj now.  Note
+   that you may need to set includeAntRuntime to false in order to
+   have full control.
+   Bugzilla Report 34638.
+
 Other changes:
 --------------
 
diff --git a/docs/manual/CoreTasks/javac.html b/docs/manual/CoreTasks/javac.html
index 0d5f9c63a..c3593af2e 100644
--- a/docs/manual/CoreTasks/javac.html
+++ b/docs/manual/CoreTasks/javac.html
@@ -295,7 +295,11 @@ invoking the compiler.</p>
     <td valign="top">includeJavaRuntime</td>
     <td valign="top">Whether to include the default run-time
       libraries from the executing VM in the classpath;
-      defaults to <code>no</code>.</td>
+      defaults to <code>no</code>.<br/>
+      <b>Note:</b> In some setups the run-time libraries may be part
+      of the "Ant run-time libraries" so you may need to explicitly
+      set includeAntRuntime to false to ensure that the Java
+      run-time libraries are not included.</td>
     <td align="center" valign="top">No</td>
   </tr>
   <tr>
diff --git a/src/main/org/apache/tools/ant/taskdefs/compilers/Gcj.java b/src/main/org/apache/tools/ant/taskdefs/compilers/Gcj.java
index 160d3fcdc..cae497fbd 100644
--- a/src/main/org/apache/tools/ant/taskdefs/compilers/Gcj.java
+++ b/src/main/org/apache/tools/ant/taskdefs/compilers/Gcj.java
@@ -66,7 +66,9 @@ public class Gcj extends DefaultCompilerAdapter {
 
         // gcj doesn't support an extension dir (-extdir)
         // so we'll emulate it for compatibility and convenience.
-        classpath.addExtdirs(extdirs);
+        if (extdirs != null || includeJavaRuntime) {
+            classpath.addExtdirs(extdirs);
+        }
 
         classpath.append(getCompileClasspath());