Hello. In my opinion this is a pretty major deficiency. I was trying to add definitions to my ~/.mailcap file (which should take priority over system mailcap files) but they weren't getting applied because of the wildcard bug. This was prohibiting me from using mailcap, so I wrote a patch and submitted it to PyPI. I've never contributed before; what would be the first step towards submitting this to python?

https://github.com/michael-lazar/mailcap_fix
https://pypi.python.org/pypi/mailcap-fix/0.1.0