Use common GCC visibility test.

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>
(cherry picked from commit 83e4c4d56c)

CMakeLists.txt

@@ -999,16 +999,9 @@ endif( )
 
 
 ##### check for gcc visibility support #########
-# FIXME
-# This should check for [T]Qt3 visibility support
 
 if( WITH_GCC_VISIBILITY )
-  if( NOT UNIX )
-    message(FATAL_ERROR "\ngcc visibility support was requested, but your system is not *NIX" )
-  endif( NOT UNIX )
-  set( __KDE_HAVE_GCC_VISIBILITY 1 )
-  set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden -fvisibility-inlines-hidden")
-  set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden -fvisibility-inlines-hidden")
+  tde_setup_gcc_visibility( )
 endif( )