Don't include ext dir for microsoft jvc when java runtime is excluded.

PR:	18055


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@275049 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/compilers/Jvc.java

@@ -89,9 +89,11 @@ public class Jvc extends DefaultCompilerAdapter {
             classpath.append(bootclasspath);
         }
 
-        // jvc doesn't support an extension dir (-extdir)
-        // so we'll emulate it for compatibility and convenience.
-        classpath.addExtdirs(extdirs);
+        if (includeJavaRuntime) {
+            // jvc doesn't support an extension dir (-extdir)
+            // so we'll emulate it for compatibility and convenience.
+            classpath.addExtdirs(extdirs);
+        }
 
         classpath.append(getCompileClasspath());