Index: build_ext.py
===================================================================
--- build_ext.py	(revision 45819)
+++ build_ext.py	(working copy)
@@ -524,7 +524,8 @@
         if self.swig_cpp:
             log.warn("--swig-cpp is deprecated - use --swig-opts=-c++")
 
-        if self.swig_cpp or ('-c++' in self.swig_opts):
+        if self.swig_cpp or ('-c++' in self.swig_opts) or \
+           ('-c++' in extension.swig_opts):
             target_ext = '.cpp'
         else:
             target_ext = '.c'