fix ProGuarded openjdk-src build

This makes a simple "hello, world!" app work, at least.  Further
changes may be needed for more sophisticated apps.

openjdk.pro

@@ -11,6 +11,7 @@
 
 -keep class java.lang.System {
    private static void initializeSystemClass();
+   public static void setProperties(java.util.Properties);
  }
 
 -keep class java.lang.ClassLoader {
@@ -33,6 +34,11 @@
 
 -keep class java.util.Properties {
    public java.lang.Object setProperty(java.lang.String, java.lang.String);
+   public java.lang.String getProperty(java.lang.String);
+ }
+
+-keep class java.util.Hashtable {
+   public java.lang.Object remove(java.lang.Object);
  }
 
 -keep class avian.OpenJDK {

src/classpath-openjdk.cpp

@@ -1777,10 +1777,14 @@ intercept(Thread* t, object c, const char* name, const char* spec,
 
     set(t, runtimeData, MethodRuntimeDataNative, native);
   } else {
-    fprintf(stderr, "unable to find %s%s in %s\n",
-            name, spec, &byteArrayBody(t, className(t, c), 0));
+    // If we can't find the method, just ignore it, since ProGuard may
+    // have stripped it out as unused.  Otherwise, the code below can
+    // be uncommented for debugging purposes.
 
-    abort(t);
+    // fprintf(stderr, "unable to find %s%s in %s\n",
+    //         name, spec, &byteArrayBody(t, className(t, c), 0));
+
+    // abort(t);
   }
 }