Fix Python bindings build with gcc < 4

bindings/python/wscript

@@ -71,7 +71,8 @@ def configure(conf):
         return
 
     # -fvisibility=hidden optimization
-    if conf.env['CXX_NAME'] == 'gcc' and conf.check_compilation_flag('-fvisibility=hidden'):
+    if (conf.env['CXX_NAME'] == 'gcc' and [int(x) for x in conf.env['CC_VERSION']] >= [4,0,0]
+        and conf.check_compilation_flag('-fvisibility=hidden')):
         conf.env.append_value('CXXFLAGS_PYEXT', '-fvisibility=hidden')
         conf.env.append_value('CCFLAGS_PYEXT', '-fvisibility=hidden')