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/Frontend/PrintPreprocessedOutput.cpp b/lib/Frontend/PrintPreprocessedOutput.cpp
index 8c32c24..4a6f8db 100644
--- a/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -139,7 +139,7 @@
   void PragmaDiagnosticPush(SourceLocation Loc, StringRef Namespace) override;
   void PragmaDiagnosticPop(SourceLocation Loc, StringRef Namespace) override;
   void PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
-                        diag::Mapping Map, StringRef Str) override;
+                        diag::Severity Map, StringRef Str) override;
   void PragmaWarning(SourceLocation Loc, StringRef WarningSpec,
                      ArrayRef<int> Ids) override;
   void PragmaWarningPush(SourceLocation Loc, int Level) override;
@@ -439,26 +439,27 @@
   setEmittedDirectiveOnThisLine();
 }
 
-void PrintPPOutputPPCallbacks::
-PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
-                 diag::Mapping Map, StringRef Str) {
+void PrintPPOutputPPCallbacks::PragmaDiagnostic(SourceLocation Loc,
+                                                StringRef Namespace,
+                                                diag::Severity Map,
+                                                StringRef Str) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
   OS << "#pragma " << Namespace << " diagnostic ";
   switch (Map) {
-  case diag::MAP_REMARK:
+  case diag::Severity::Remark:
     OS << "remark";
     break;
-  case diag::MAP_WARNING:
+  case diag::Severity::Warning:
     OS << "warning";
     break;
-  case diag::MAP_ERROR:
+  case diag::Severity::Error:
     OS << "error";
     break;
-  case diag::MAP_IGNORE:
+  case diag::Severity::Ignored:
     OS << "ignored";
     break;
-  case diag::MAP_FATAL:
+  case diag::Severity::Fatal:
     OS << "fatal";
     break;
   }