Cannot install on OSX

[richardipsum]

Hi, I recently packaged your library for NixOS, the CI builds Darwin as well as Linux by default. There seem to be a number of issues that prevent this from working with OSX.

I fixed a bunch of things but finally when I try to run the example.lua file included in this git repo I get the following:

sh-3.2# lua test_iconv.lua 
lua: error loading module 'iconv' from file '/usr/local/lib/lua/5.2/iconv.so':
        dlopen(/usr/local/lib/lua/5.2/iconv.so, 6): Symbol not found: _iconv
  Referenced from: /usr/local/lib/lua/5.2/iconv.so
  Expected in: flat namespace
 in /usr/local/lib/lua/5.2/iconv.so
stack traceback:
        [C]: in ?
        [C]: in function 'require'
        test_iconv.lua:3: in main chunk
        [C]: in ?

I've been able to package another lua binding on OSX without issue, I'm not sure I understand why this binding should be any different. Fwiw, I also modified the Makefile to link with libiconv, so it's not clear to me why the symbol cannot be found.

Thanks, Richard