[Win32] sample-gai.c should call WSAStartup()

I fail to get the lib/sample/sample-gai.c to work on Windows since WSAStartup() wasn't called anywhere AFAICS.

The replacement function getaddrinfo() calls getservbyname() (not replaced). This call fails due to a missing WSAStartup().

An easy fix would simply be:

--- a/lib/samples/sample-gai.c 2018-06-07 17:54:40
+++ a/lib/samples/sample-gai.c 2018-10-12 03:39:26
@@ -62,6 +62,17 @@

 int
 main(int argc, char *argv[]) {
+#ifdef _WIN32
+       WORD    wVersionRequested = MAKEWORD(2, 2);
+       WSADATA wsaData;
+       int     err = WSAStartup(wVersionRequested, &wsaData);
+
+       if (err != 0) {
+               fprintf(stderr, "WSAStartup() failed: %d\n", err);
+               return (1);
+       }
+#endif
+
        if (argc < 2)
                exit(1);

@@ -69,5 +80,8 @@
        do_gai(AF_INET6, argv[1]);
        do_gai(AF_UNSPEC, argv[1]);

+#ifdef _WIN32
+       WSACleanup();
+#endif
        return (0);
 }