Signal handling, take 2.

runtime/bin/signal_blocker.h

Index: runtime/bin/signal_blocker.h
diff --git a/runtime/bin/signal_blocker.h b/runtime/bin/signal_blocker.h
index 58e8d7eb00bdf5dfb568efcd6f5d9f9a5fbb7b61..1ab816c145deda0af496c680557b4b146199b433 100644
--- a/runtime/bin/signal_blocker.h
+++ b/runtime/bin/signal_blocker.h
@@ -26,12 +26,26 @@ class ThreadSignalBlocker {
     sigaddset(&signal_mask, sig);
     // Add sig to signal mask.
     int r = pthread_sigmask(SIG_BLOCK, &signal_mask, &old);
+    USE(r);
+    ASSERT(r == 0);
+  }
+
+  ThreadSignalBlocker(int sigs_count, const int sigs[]) {
+    sigset_t signal_mask;
+    sigemptyset(&signal_mask);
+    for (int i = 0; i < sigs_count; i++) {
+      sigaddset(&signal_mask, sigs[i]);
+    }
+    // Add sig to signal mask.
+    int r = pthread_sigmask(SIG_BLOCK, &signal_mask, &old);
+    USE(r);
     ASSERT(r == 0);
   }
 
   ~ThreadSignalBlocker() {
     // Restore signal mask.
     int r = pthread_sigmask(SIG_SETMASK, &old, NULL);
+    USE(r);
     ASSERT(r == 0);
   }