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/lib/Basic/Builtins.cpp b/lib/Basic/Builtins.cpp
index 6c78dc3..8efcac6 100644
--- a/lib/Basic/Builtins.cpp
+++ b/lib/Basic/Builtins.cpp
@@ -76,7 +76,7 @@
 
   // Step #2: Register target-specific builtins.
   for (unsigned i = 0, e = NumTSRecords; i != e; ++i)
-    if (!LangOpts.NoBuiltin || !strchr(TSRecords[i].Attributes, 'f'))
+    if (BuiltinIsSupported(TSRecords[i], LangOpts))
       Table.get(TSRecords[i].Name).setBuiltinID(i+Builtin::FirstTSBuiltin);
 }