In file included from getifaddrs.c:15:
In file included from ./getifaddrs-internal.h:42:
/usr/include/resolv.h:137:14: error: array has incomplete element type 'struct sockaddr_in'
                nsaddr_list[MAXNS];     /* address of name server */

Index: cups/getifaddrs-internal.h
--- cups/getifaddrs-internal.h.orig
+++ cups/getifaddrs-internal.h
@@ -40,6 +40,7 @@ typedef int socklen_t;
 #  endif /* __APPLE__ && !_SOCKLEN_T */
 
 #  ifndef _WIN32
+#    include <netinet/in.h>
 #    include <net/if.h>
 #    include <resolv.h>
 #    ifdef HAVE_GETIFADDRS