Add temporary workaround for boringssl attempting to access the auxillary vector

sky/shell/ios/main_ios.mm

Index: sky/shell/ios/main_ios.mm
diff --git a/sky/shell/ios/main_ios.mm b/sky/shell/ios/main_ios.mm
index f0020606e2c9542e8781b6937f4849f9615f6ccc..b0eb2042a8ad8fc219a1c37ab46e7ed65a7f1275 100644
--- a/sky/shell/ios/main_ios.mm
+++ b/sky/shell/ios/main_ios.mm
@@ -12,6 +12,16 @@
 #include "base/mac/scoped_nsautorelease_pool.h"
 #include "ui/gl/gl_surface.h"
 
+extern "C" {
+// TODO(csg): HACK! boringssl accesses this on Android using a weak symbol
+// instead of a global. Till the patch for that lands and propagates to Sky, we
+// specify the same here to get workable builds on iOS. This is a hack! Will
+// go away.
+unsigned long getauxval(unsigned long type) {
+  return 0;
+}
+}
+
 static void InitializeLogging() {
   logging::LoggingSettings settings;
   settings.logging_dest = logging::LOG_TO_SYSTEM_DEBUG_LOG;