libvncclient: replace gethostbyname() with getaddrinfo()

man gethostbyname:
"The gethostbyname*(), gethostbyaddr*(), herror(), and hstrerror() functions are obsolete.  Applications should use getaddrinfo(3), getnameinfo(3), and gai_strerror(3) instead."

Furthermore, the man page states that `gethostbyname()` is MT-Unsafe, probably due to the fact that it retuns a pointer to static data. Thus, by using `getaddrinfo()`, we improve the multithreading soundness of LibVNCClient.

Author: badda71

libvncclient/sockets.c

@@ -812,7 +812,7 @@ SetDSCP(rfbSocket sock, int dscp)
 rfbBool
 StringToIPAddr(const char *str, unsigned int *addr)
 {
-  struct hostent *hp;
+  struct addrinfo hints, *res;
 
   if (strcmp(str,"") == 0) {
     *addr = htonl(INADDR_LOOPBACK); /* local */
@@ -824,17 +824,20 @@ StringToIPAddr(const char *str, unsigned int *addr)
   if (*addr != -1)
     return TRUE;
 
-  hp = gethostbyname(str);
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family   = AF_INET;
+  hints.ai_socktype = SOCK_STREAM;
+
+  if (getaddrinfo(str, NULL, &hints, &res) == 0) {
+    *addr = (((struct sockaddr_in *)res->ai_addr)->sin_addr.s_addr);
+    freeaddrinfo(res);
 
-  if (hp) {
-    *addr = *(unsigned int *)hp->h_addr;
     return TRUE;
   }
 
   return FALSE;
 }
 
-
 /*
  * Test if the other end of a socket is on the same machine.
  */