Simplify the compiler feature check

Modules/GenerateExportHeader.cmake

@@ -142,12 +142,10 @@ macro(_DO_SET_MACRO_VALUES TARGET_LIBRARY)
     if(WIN32)
       set(DEFINE_EXPORT "__declspec(dllexport)")
       set(DEFINE_IMPORT "__declspec(dllimport)")
-    elseif(CMAKE_COMPILER_IS_GNUCXX OR (${CMAKE_CXX_COMPILER_ID} MATCHES Intel AND UNIX))
-      if(COMPILER_HAS_HIDDEN_VISIBILITY AND USE_COMPILER_HIDDEN_VISIBILITY)
-        set(DEFINE_EXPORT "__attribute__((visibility(\"default\")))")
-        set(DEFINE_IMPORT "__attribute__((visibility(\"default\")))")
-        set(DEFINE_NO_EXPORT "__attribute__((visibility(\"hidden\")))")
-      endif()
+    elseif(COMPILER_HAS_HIDDEN_VISIBILITY AND USE_COMPILER_HIDDEN_VISIBILITY)
+      set(DEFINE_EXPORT "__attribute__((visibility(\"default\")))")
+      set(DEFINE_IMPORT "__attribute__((visibility(\"default\")))")
+      set(DEFINE_NO_EXPORT "__attribute__((visibility(\"hidden\")))")
     endif()
   endif()
 endmacro()