Link convention fixes

Hi all,
  I'm currently working on fixing the (many) instances of wrong call
conventions (pointers to extern C functions being stored as variables
where a c++ linkage is specified). Those are not fatal, but getting
rid of them would make clearer what is c++ -clean and what is not.
There is one case where this cannot really be done, and that's xxfree.

How would you suggest addressing this? The best idea i have is to
duplicate the code somehow in a .cc file, and rename the c
implementation as 'cxfree'.

Thanks

-- 
    /kinkie