Skip socket tests on Windows platform.

Some test may be OK but we skip everything as a starting point.

mrbgems/mruby-socket/test/ipsocket.rb

+unless SocketTest.win?
+
 # Note: most of tests below will fail if UDPSocket is broken.
 
 assert('IPSocket.getaddress') do
@@ -38,3 +40,5 @@ assert('IPSocket.peeraddr') do
   server.close
   true
 end
+
+end # win?

mrbgems/mruby-socket/test/socket.rb

+unless SocketTest.win?
+
 assert('Socket.gethostname') do
   assert_true(Socket.gethostname.is_a? String)
 end
@@ -32,3 +34,5 @@ assert('Socket#recvfrom') do
     c.close rescue nil
   end
 end
+
+end   # win?

mrbgems/mruby-socket/test/sockettest.c

@@ -12,9 +12,20 @@ mrb_sockettest_tmppath(mrb_state *mrb, mrb_value klass)
   return str;
 }
 
+mrb_value
+mrb_sockettest_win_p(mrb_state *mrb, mrb_value klass)
+{
+#ifdef _WIN32
+  return mrb_true_value();
+#else
+  return mrb_false_value();
+#endif
+}
+
 void
 mrb_mruby_socket_gem_test(mrb_state* mrb)
 {
   struct RClass *c = mrb_define_module(mrb, "SocketTest");
   mrb_define_class_method(mrb, c, "tmppath", mrb_sockettest_tmppath, MRB_ARGS_NONE());
+  mrb_define_class_method(mrb, c, "win?", mrb_sockettest_win_p, MRB_ARGS_NONE());
 }

mrbgems/mruby-socket/test/unix.rb

+unless SocketTest.win?
+
 def unixserver_test_block
   path = SocketTest.tmppath
   File.unlink path rescue nil
@@ -124,3 +126,5 @@ assert('UNIXSocket#recvfrom') do
     # a[1][1] would be "" or something
   end
 end
+
+end  # win?