Fix compilation error due to duplicated symbols

duplicate symbol _getdns_error in:
    build/temp.macosx-10.9-intel-2.7/getdns.o
    build/temp.macosx-10.9-intel-2.7/pygetdns_util.o
duplicate symbol _getdns_error in:
    build/temp.macosx-10.9-intel-2.7/getdns.o
    build/temp.macosx-10.9-intel-2.7/fd_poller.o
duplicate symbol _getdns_error in:
    build/temp.macosx-10.9-intel-2.7/getdns.o
    build/temp.macosx-10.9-intel-2.7/context.o
ld: 3 duplicate symbols for architecture x86_64

Author: saghul

getdns.c

@@ -46,6 +46,9 @@
 #include <pthread.h>
 #include "pygetdns.h"
 
+#include "context.c"
+#include "fd_poller.c"
+#include "pygetdns_util.c"
 
 
 PyMethodDef Context_methods[] = {

setup.py

@@ -42,7 +42,7 @@
                     include_dirs = [ '/usr/local/include', ],
                     libraries = [ 'ldns', 'getdns', 'getdns_ext_event' ],
                     library_dirs = [ '/usr/local/lib' ],
-                    sources = [ 'getdns.c', 'pygetdns_util.c', 'fd_poller.c', 'context.c' ],
+                    sources = [ 'getdns.c' ],
                     runtime_library_dirs = [ '/usr/local/lib' ]
                     )