Merge pull request #9538 from huiwangcs/ingore_weak_symbol_macos

ignore weak symbol under mac because it must be defined

CMakeLists.txt

@@ -214,6 +214,10 @@ if (COMPILER_CLANG)
     # TODO investigate that
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-omit-frame-pointer")
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fno-omit-frame-pointer")
+    if (OS_DARWIN)
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wl,-U,_inside_main")
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wl,-U,_inside_main")
+    endif()
 endif ()
 
 option (ENABLE_LIBRARIES "Enable all libraries (Global default switch)" ON)