Missing check for python-dev library in autoconf

Maybe this is fixed in SVN so I'll keep it short. The configure check
for bro1.5 doesn't verify that the python development libraries are
installed. I am running Ubuntu 9.10 x64. When running ./configure &&
make the following error pops up.

broccoli_intern_wrap.c:118:20: error: Python.h: No such file or directory

Installing the python-dev package on ubuntu allows me to compile but I
figure it'd be nice to add that check in the autoconf. Unfortunately I
don't know autoconf at all so I can't provide a patch which does that.