Fix -std=c++11 flag

CMakeLists.txt

 cmake_minimum_required(VERSION 2.8.8)
-add_definitions(-std=c++11)
+
+if (CMAKE_VERSION VERSION_LESS "3.1")
+  add_definitions(-std=c++11)
+else()
+  set(CMAKE_CXX_STANDARD 11)
+endif()
 
 if (POLICY CMP0048)
   cmake_policy(SET CMP0048 NEW)

googletest/cmake/internal_utils.cmake

@@ -98,6 +98,10 @@ macro(config_compiler_and_linker)
     set(cxx_exception_flags "-EHsc -D_HAS_EXCEPTIONS=1")
     set(cxx_no_exception_flags "-EHs-c- -D_HAS_EXCEPTIONS=0")
     set(cxx_no_rtti_flags "-GR-")
+
+    if (${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
+      set(cxx_base_flags "${cxx_base_flags} -Wno-unknown-argument")
+    endif()
   elseif (CMAKE_COMPILER_IS_GNUCXX)
     set(cxx_base_flags "-Wall -Wshadow -Werror")
     if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 7.0.0)