Add a cast in ForwardLookup() to fix a gcc warning on Cygwin

This fixes the following warning message of 4.5.3 on Cygwin:

 resolve.c: In function ‘ForwardLookup’:
 resolve.c:273:21: warning: comparison between signed and
                   unsigned integer expressions

1 files changed, 1 insertions, 1 deletions

diff --git a/src/ngircd/resolve.c b/src/ngircd/resolve.c
index c7e60038..3f99b3a9 100644
--- a/src/ngircd/resolve.c
+++ b/src/ngircd/resolve.c
@@ -270,7 +270,7 @@ ForwardLookup(const char *hostname, array *IpAddr, int af)
 	for (a = ai_results; a != NULL; a = a->ai_next) {
 		assert(a->ai_addrlen <= sizeof(addr));
 
-		if (a->ai_addrlen > sizeof(addr))
+		if ((size_t)a->ai_addrlen > sizeof(addr))
 			continue;
 
 		memcpy(&addr, a->ai_addr, a->ai_addrlen);