Fix copyrights.

com.oracle.truffle.r.ffi.impl/src/com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_Base.java

 /*
- * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it

com.oracle.truffle.r.ffi.impl/src/com/oracle/truffle/r/ffi/impl/managed/Managed_Base.java

 /*
- * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it

com.oracle.truffle.r.ffi.impl/src/com/oracle/truffle/r/ffi/impl/nfi/TruffleNFI_Base.java

 /*
- * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it

com.oracle.truffle.r.native/fficall/src/truffle_common/base_rffi.c

 /*
- * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it

com.oracle.truffle.r.runtime/src/com/oracle/truffle/r/runtime/ffi/BaseRFFI.java

 /*
- * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it