This is a question for our Linux guys

We use the following code to export solely the public API functions (the some ones as for Win32):
Code:
#if defined( __GNUC__ ) && __GNUC__ >= 4
# define DLLEXP extern "C" __attribute__ ((visibility("default")))
#else
However, from what I can see, the visibility of all other symbols is not hidden. Should we add the following to the Horde3D and Horde3DUtils CMake files or do I miss something?
Code:
# Hide all symbols except the ones which are explicitly marked as visible
if(CMAKE_COMPILER_IS_GNUCXX)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden")
endif(CMAKE_COMPILER_IS_GNUCXX)
Note: the GCC version is not checked