Ignoring annoying 'unused private field' warning

Change-Id: If4f4cbd82edf6152789da196e0b5d40cbe8729f5
diff --git a/wscript b/wscript
index 5b0e6a5..b9b9410 100644
--- a/wscript
+++ b/wscript
@@ -116,7 +116,7 @@
 
     if conf.options.debug:
         conf.define ('_DEBUG', 1)
-        conf.env.append_value('CXXFLAGS', ['-O0', '-Wall', '-Wno-unused-variable', '-g3'])
+        conf.env.append_value('CXXFLAGS', ['-O0', '-Wall', '-Wno-unused-variable', '-Wno-unused-private-field', '-g3'])
     else:
         conf.env.append_value('CXXFLAGS', ['-O3', '-g'])