external/boringssl: Sync to ba94746eb2b4b59a0eb72047e4ca2d2d54454c87.

This includes the following changes:

https://boringssl.googlesource.com/boringssl/+log/7f8c553d7f4db0a6ce727f2986d41bf8fe8ec4bf..ba94746eb2b4b59a0eb72047e4ca2d2d54454c87

Test: BoringSSL CTS Presubmits
Change-Id: I5283ca8ec80f4abbc2543fece2ecf2b33240c6e4
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1814b13..1f2f6ba 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -72,6 +72,9 @@
 
   if(NOT MSVC)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+    if(APPLE)
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
+    endif()
     if(NOT BORINGSSL_ALLOW_CXX_RUNTIME)
       set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-exceptions -fno-rtti")
     endif()
@@ -307,7 +310,7 @@
   set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -march=${CMAKE_SYSTEM_PROCESSOR}")
 endif()
 
-if (${ARCH} STREQUAL "x86" AND APPLE)
+if (${ARCH} STREQUAL "x86" AND APPLE AND ${CMAKE_VERSION} VERSION_LESS "3.0")
   # With CMake 2.8.x, ${CMAKE_SYSTEM_PROCESSOR} evalutes to i386 on OS X,
   # but clang defaults to 64-bit builds on OS X unless otherwise told.
   # Set ARCH to x86_64 so clang and CMake agree. This is fixed in CMake 3.