Modify RayLogLevel to avoid conflicts with DEBUG macro and ERROR macros that are defined externally (#6204)

* Prevent name collision of ERROR macro from Windows with RayLogLevel::ERROR

src/ray/util/logging.h

@@ -4,6 +4,21 @@
 #include <iostream>
 #include <string>
 
+#if defined(_WIN32)
+#ifndef _WINDOWS_
+#ifndef WIN32_LEAN_AND_MEAN  // Sorry for the inconvenience. Please include any related
+                             // headers you need manually.
+                             // (https://stackoverflow.com/a/8294669)
+#define WIN32_LEAN_AND_MEAN  // Prevent inclusion of WinSock2.h
+#endif
+#include <Windows.h>  // Force inclusion of WinGDI here to resolve name conflict
+#endif
+#ifdef ERROR  // Should be true unless someone else undef'd it already
+#undef ERROR  // Windows GDI defines this macro; make it a global enum so it doesn't
+              // conflict with our code
+enum { ERROR = 0 };
+#endif
+#endif
 namespace ray {
 
 enum class RayLogLevel { DEBUG = -1, INFO = 0, WARNING = 1, ERROR = 2, FATAL = 3 };