Revert "Revert "Upgrade to 5.0.71.48"" DO NOT MERGE

This reverts commit f2e3994fa5148cc3d9946666f0b0596290192b0e,
and updates the x64 makefile properly so it doesn't break that
build.

FPIIM-449

Change-Id: Ib83e35bfbae6af627451c926a9650ec57c045605
(cherry picked from commit 109988c7ccb6f3fd1a58574fa3dfb88beaef6632)
diff --git a/third_party/llvm-build/Release+Asserts/lib/clang/3.9.0/include/rdseedintrin.h b/third_party/llvm-build/Release+Asserts/lib/clang/3.9.0/include/rdseedintrin.h
new file mode 100644
index 0000000..421f4ea
--- /dev/null
+++ b/third_party/llvm-build/Release+Asserts/lib/clang/3.9.0/include/rdseedintrin.h
@@ -0,0 +1,56 @@
+/*===---- rdseedintrin.h - RDSEED intrinsics -------------------------------===
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __X86INTRIN_H
+#error "Never use <rdseedintrin.h> directly; include <x86intrin.h> instead."
+#endif
+
+#ifndef __RDSEEDINTRIN_H
+#define __RDSEEDINTRIN_H
+
+/* Define the default attributes for the functions in this file. */
+#define __DEFAULT_FN_ATTRS __attribute__((__always_inline__, __nodebug__, __target__("rdseed")))
+
+static __inline__ int __DEFAULT_FN_ATTRS
+_rdseed16_step(unsigned short *__p)
+{
+  return __builtin_ia32_rdseed16_step(__p);
+}
+
+static __inline__ int __DEFAULT_FN_ATTRS
+_rdseed32_step(unsigned int *__p)
+{
+  return __builtin_ia32_rdseed32_step(__p);
+}
+
+#ifdef __x86_64__
+static __inline__ int __DEFAULT_FN_ATTRS
+_rdseed64_step(unsigned long long *__p)
+{
+  return __builtin_ia32_rdseed64_step(__p);
+}
+#endif
+
+#undef __DEFAULT_FN_ATTRS
+
+#endif /* __RDSEEDINTRIN_H */