Add cmake support for WITH_GCC_VISIBILITY.

ConfigureChecks.cmake

@@ -1,3 +1,17 @@
+##### check for gcc visibility support #########
+# FIXME
+# This should check for [T]Qt3 visibility support
+
+if( WITH_GCC_VISIBILITY )
+  if( NOT UNIX )
+    tde_message_fatal(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")
+endif( )
+
+
 # required stuff
 find_package( TQt )
 find_package( TDE )