[cmake] Enable C++11 on CMake (#1519)

CMakeLists.txt

@@ -552,7 +552,7 @@ endif ()
 if (UNIX OR MINGW)
   # Make symbols link locally
   include (CheckCXXCompilerFlag)
-  check_cxx_compiler_flag(-Bsymbolic-functions CXX_SUPPORTS_FLAG_BSYMB_FUNCS)
+  CHECK_CXX_COMPILER_FLAG(-Bsymbolic-functions CXX_SUPPORTS_FLAG_BSYMB_FUNCS)
   if (CXX_SUPPORTS_FLAG_BSYMB_FUNCS)
     link_libraries(-Bsymbolic-functions)
   endif ()
@@ -570,8 +570,16 @@ if (UNIX OR MINGW)
     # No threadsafe statics as we do it ourselves
     set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-threadsafe-statics")
   endif ()
+
+  CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11)
+  if (COMPILER_SUPPORTS_CXX11)
+    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+  else()
+    message(STATUS "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Please use a different C++ compiler.")
+  endif()
 endif ()
 
+
 ## Define harfbuzz-gobject library
 if (HB_HAVE_GOBJECT)
   add_library(harfbuzz-gobject