bind: avoid crashes from SIGPIPE

The Go runtime doesn't handle SIGIPE signals from writing to closed
sockets or pipes in c-archive and c-shared mode (issue 17393).
Work around it in gomobile by simply ignoring all SIGPIPE signals;
they're not useful in mobile apps anyway.

Change-Id: Ibd7ee41058856c5eddb4a519345a3851a29e9b44
Reviewed-on: https://go-review.googlesource.com/33771
Reviewed-by: David Crawshaw <crawshaw@golang.org>

bind/java/SeqTest.java

@@ -577,4 +577,8 @@ public class SeqTest extends InstrumentationTestCase {
     InitCaller initer = Testpkg.newInitCaller();
     initer.init();
   }
+
+  public void testSIGPIPE() {
+    Testpkg.testSIGPIPE();
+  }
 }