Update Clang for rebase to r212749.

This also fixes a small issue with arm_neon.h not being generated always.

Includes a cherry-pick of:
r213450 - fixes mac-specific header issue
r213126 - removes a default -Bsymbolic on Android

Change-Id: I2a790a0f5d3b2aab11de596fc3a74e7cbc99081d
diff --git a/test/CodeGenCXX/microsoft-abi-structors-alias.cpp b/test/CodeGenCXX/microsoft-abi-structors-alias.cpp
index 59ced74..f977556 100644
--- a/test/CodeGenCXX/microsoft-abi-structors-alias.cpp
+++ b/test/CodeGenCXX/microsoft-abi-structors-alias.cpp
@@ -22,5 +22,5 @@
 void foo() {
   B b;
 }
-// CHECK-DAG: @"\01??1B@test2@@UAE@XZ" = alias void (%"struct.test2::B"*), void (%"struct.test2::A"*)* @"\01??1A@test2@@UAE@XZ"
+// CHECK-DAG: @"\01??1B@test2@@UAE@XZ" = alias bitcast (void (%"struct.test2::A"*)* @"\01??1A@test2@@UAE@XZ" to void (%"struct.test2::B"*)*)
 }