Fix #1453 - do not allow empty wakeup buffer

src/arch_win32.h

@@ -15,6 +15,7 @@
 #endif
 
 #include <ctype.h>
+#include <direct.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
@@ -70,6 +71,7 @@ typedef int socklen_t;
 
 #define realpath(a, b) _fullpath((b), (a), MG_PATH_MAX)
 #define sleep(x) Sleep(x)
+#define mkdir(a, b) _mkdir(a)
 
 #ifndef va_copy
 #ifdef __va_copy