[222] Fix will retained flag handling on Windows.

Thanks to codami.

Bug: https://github.com/eclipse/mosquitto/issues/222

ChangeLog.txt

@@ -10,6 +10,7 @@ Broker:
 - Call fsync after persisting data to ensure it is correctly written. Closes
   #189.
 - Fix persistence saving of subscription QoS on big-endian machines.
+- Fix will retained flag handling on Windows. Closes #222.
 
 Client library:
 - Support OpenSSL 1.1.0.

src/read_handle_server.c

@@ -180,7 +180,7 @@ int mqtt3_handle_connect(struct mosquitto_db *db, struct mosquitto *context)
 		rc = MOSQ_ERR_PROTOCOL;
 		goto handle_connect_error;
 	}
-	will_retain = connect_flags & 0x20;
+	will_retain = ((connect_flags & 0x20) == 0x20); // Temporary hack because MSVC<1800 doesn't have stdbool.h.
 	password_flag = connect_flags & 0x40;
 	username_flag = connect_flags & 0x80;