On the SWIG mailing list William S Fulton pointed out that identifiers like ___result_voidstar are, technically speaking, illegal in that they are reserved names in C99 and C++. I don't care too much, it seems more of an academic issue than one that could cause practical problems anytime soon, but I thought I'd pass this on to you.
http://groups.google.com/group/comp.std.c++/browse_thread/thread/64571795425...
http://sourceforge.net/mailarchive/message.php?msg_name=4AD39AE4.9020600%40f...