Avert a crash and file descriptor leak in yank-media

* java/org/gnu/emacs/EmacsNative.java (close): New declaration.

* java/org/gnu/emacs/EmacsSdk11Clipboard.java
(getClipboardData): Catch SecurityException and guarantee file
descriptors are closed even if exceptions arise.

* src/android.c (dup): Export another function.

java/org/gnu/emacs/EmacsNative.java

@@ -39,6 +39,9 @@ public final class EmacsNative
   /* Like `dup' in C.  */
   public static native int dup (int fd);
 
+  /* Like `close' in C.  */
+  public static native int close (int fd);
+
   /* Obtain the fingerprint of this build of Emacs.  The fingerprint
      can be used to determine the dump file name.  */
   public static native String getFingerprint ();