Check for working getaddrinfo() function

At least AIX 4.3.3 and 5.1 have a broken implementation of getaddrinfo()
which doesn't handle "0" as numeric service correctly. This patch adds
a configure check for this case and changes all calling functions to only
use getaddrinfo() if it "works".

See <http://www.stacken.kth.se/lists/heimdal-discuss/2004-05/msg00059.html>

(cherry picked from commit b8433e9261)

Conflicts:
	configure.ng

src/ipaddr/ng_ipaddr.c

@@ -23,7 +23,7 @@
 GLOBAL bool
 ng_ipaddr_init(ng_ipaddr_t *addr, const char *ip_str, UINT16 port)
 {
-#ifdef HAVE_GETADDRINFO
+#ifdef HAVE_WORKING_GETADDRINFO
 	int ret;
 	char portstr[64];
 	struct addrinfo *res0;

src/ngircd/resolve.c

@@ -242,7 +242,7 @@ ForwardLookup(const char *hostname, array *IpAddr, int af)
 {
 	ng_ipaddr_t addr;
 
-#ifdef HAVE_GETADDRINFO
+#ifdef HAVE_WORKING_GETADDRINFO
 	int res;
 	struct addrinfo *a, *ai_results;
 	static struct addrinfo hints;