modify sed commands to handle non-GNU and GNU od

Another one-line fix :) tested on solaris, seems to generate identical browse_py.h
okay i think i have a more portable fix. 
I'm having difficulty figuring out how to submit it, though.
When I tried to clone again, and commit to branch, it gave me errors  like
 ! [rejected]        inline-fix -> inline-fix (non-fast-forward)

So.. I used the web interface to edit the file again :-/
Hope that works.
I also improved a comments a bit.