use std=gnu++11 compiler flag instead of std=c++11

On g++ 4.9, std=c++11 would disable the “Q” __float128 literal suffix which is used by boost library and causes compiler errors.

Author: Huang-Ming Huang

cmake/FastTypeGenTarget.cmake

@@ -31,7 +31,4 @@ function (FASTTYPEGEN_TARGET Name)
   set("FASTTYPEGEN_${Name}_OUTPUTS" "${FASTTYPEGEN_${Name}_OUTPUTS}" PARENT_SCOPE)
   set("FASTTYPEGEN_${Name}_DEFINED" TRUE PARENT_SCOPE)
   set("FASTTYPEGEN_${Name}_INPUTS" "${ARGN}" PARENT_SCOPE)
-endfunction (FASTTYPEGEN_TARGET)
-
-get_target_property(mfast_cxx mfast_static CXX_STANDARD)
-message("mfast CXX_STANDARD = ${mfast_cxx}")
+endfunction (FASTTYPEGEN_TARGET)

cmake/SetCXXStandard.cmake

@@ -4,6 +4,6 @@ set(CMAKE_CXX_STANDARD 11 CACHE INTERNAL "specifies the C++ standard whose featu
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 if (NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
   ### Even though CMAKE_CXX_STANDARD_REQUIRED is supported since CMake 3.1, it doesn't work for Emscripten em++ together with
-  ### Cmake 3.6. 
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++${CMAKE_CXX_STANDARD}")
+  ### Cmake 3.6.
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++${CMAKE_CXX_STANDARD}")
 endif()