Imported GNU Classpath 0.20

Imported GNU Classpath 0.20
       * Makefile.am (AM_CPPFLAGS): Add classpath/include.
       * java/nio/charset/spi/CharsetProvider.java: New override file.
       * java/security/Security.java: Likewise.
       * sources.am: Regenerated.
       * Makefile.in: Likewise.

From-SVN: r109831

libjava/classpath/java/io/ObjectOutputStream.java

@@ -442,6 +442,11 @@ public class ObjectOutputStream extends OutputStream
         realOutput.writeByte(flags);
 
         ObjectStreamField[] fields = osc.fields;
+
+	if (fields == ObjectStreamClass.INVALID_FIELDS)
+	  throw new InvalidClassException
+		  (osc.getName(), "serialPersistentFields is invalid");
+
         realOutput.writeShort(fields.length);
 
         ObjectStreamField field;