red-stream: Fix issue with SASL and no-Glibc

Using Unix sockets and no-Glibc C libraries (like Musl) getnameinfo
will fail causing SASL code to fail initialization.
Replicate Glibc behavior and report "localhost" as host and an
empty port string.

This fixes https://gitlab.freedesktop.org/spice/spice/-/issues/58.

Signed-off-by: Frediano Ziglio <freddy77@gmail.com>

server/red-stream.cpp

@@ -754,6 +754,11 @@ static char *addr_to_string(const char *format,
     char serv[NI_MAXSERV];
     int err;
 
+    // makes it work on no-glibc avoiding getnameinfo returning error
+    if (sa->ss_family == AF_UNIX) {
+        return g_strdup("localhost;");
+    }
+
     if ((err = getnameinfo((struct sockaddr *)sa, salen,
                            host, sizeof(host),
                            serv, sizeof(serv),