--- a/wscript	Tue Feb 14 17:57:15 2012 +0000
+++ b/wscript	Tue Feb 14 18:44:16 2012 +0000
@@ -270,6 +270,11 @@
 def report_optional_feature(conf, name, caption, was_enabled, reason_not_enabled):
     conf.env.append_value('NS3_OPTIONAL_FEATURES', [(name, caption, was_enabled, reason_not_enabled)])
 
+def check_optional_feature(conf, name):
+    for (name1, caption, was_enabled, reason_not_enabled) in conf.env.NS3_OPTIONAL_FEATURES:
+        if name1 == name:
+            return was_enabled
+    raise KeyError("Feature %r not declared yet" % (name,))
 
 # starting with waf 1.6, conf.check() becomes fatal by default if the
 # test fails, this alternative method makes the test non-fatal, as it
@@ -287,6 +292,7 @@
     conf.check_nonfatal = types.MethodType(_check_nonfatal, conf)
     conf.check_compilation_flag = types.MethodType(_check_compilation_flag, conf)
     conf.report_optional_feature = types.MethodType(report_optional_feature, conf)
+    conf.check_optional_feature = types.MethodType(check_optional_feature, conf)
     conf.env['NS3_OPTIONAL_FEATURES'] = []
 
     conf.check_tool('compiler_c')
@@ -364,6 +370,8 @@
 
     conf.env['MODULES_NOT_BUILT'] = []
 
+    conf.sub_config('bindings/python')
+
     conf.sub_config('src')
 
     # Set the list of enabled modules.
@@ -396,8 +404,6 @@
             if not conf.env['NS3_ENABLED_MODULES']:
                 raise WafError('Exiting because the ' + not_built + ' module can not be built and it was the only one enabled.')
 
-    conf.sub_config('bindings/python')
-
     conf.sub_config('src/mpi')
 
     # for suid bits