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/AST/Expr.cpp b/lib/AST/Expr.cpp
index 7e1b2d9..0cc046c 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -998,7 +998,7 @@
     TheLexer.LexFromRawLexer(TheTok);
     
     // Use the StringLiteralParser to compute the length of the string in bytes.
-    StringLiteralParser SLP(&TheTok, 1, SM, Features, Target);
+    StringLiteralParser SLP(TheTok, SM, Features, Target);
     unsigned TokNumBytes = SLP.GetStringLength();
     
     // If the byte is in this token, return the location of the byte.