add classes and methods needed for GNU Classpath compatibility

Most of these methods are stubs which throw
UnsupportedOperationExceptions for now.

classpath/java/lang/Class.java

@@ -14,12 +14,17 @@ import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
+import java.lang.reflect.Type;
+import java.lang.reflect.TypeVariable;
 import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.GenericDeclaration;
+import java.lang.annotation.Annotation;
 import java.io.InputStream;
 import java.io.IOException;
 import java.net.URL;
+import java.security.ProtectionDomain;
 
-public final class Class <T> {
+public final class Class <T> implements Type, GenericDeclaration {
   private static final int PrimitiveFlag = 1 << 4;
 
   private short flags;
@@ -434,8 +439,61 @@ public final class Class <T> {
       return null;
     }
   }
-  
+
   public boolean desiredAssertionStatus() {
     return false;
   }
+
+  public T cast(Object o) {
+    return (T) o;
+  }
+
+  public Object[] getSigners() {
+    throw new UnsupportedOperationException();
+  }
+
+  public Annotation[] getDeclaredAnnotations() {
+    throw new UnsupportedOperationException();
+  }
+
+  public boolean isEnum() {
+    throw new UnsupportedOperationException();
+  }
+
+  public TypeVariable<Class<T>>[] getTypeParameters() {
+    throw new UnsupportedOperationException();
+  }
+
+  public String getSimpleName() {
+    throw new UnsupportedOperationException();
+  }
+
+  public Method getEnclosingMethod() {
+    throw new UnsupportedOperationException();
+  }
+
+  public Constructor getEnclosingConstructor() {
+    throw new UnsupportedOperationException();
+  }
+
+  public Class getEnclosingClass() {
+    throw new UnsupportedOperationException();
+  }
+
+  public Class[] getDeclaredClasses() {
+    throw new UnsupportedOperationException();
+  }
+
+  public <A extends Annotation> A getAnnotation(Class<A> c) {
+    throw new UnsupportedOperationException();
+  }
+
+  public ProtectionDomain getProtectionDomain() {
+    throw new UnsupportedOperationException();
+  }
+
+  // for GNU Classpath compatibility:
+  void setSigners(Object[] signers) {
+    throw new UnsupportedOperationException();
+  }
 }