8264346: nullptr_t undefined in global namespace for clang+libstdc++

Reviewed-by: dholmes, kbarrett

Author: stefank

src/hotspot/share/oops/oopsHierarchy.hpp

@@ -100,8 +100,8 @@ class oop {
   bool operator==(const oop& o) const  { return _o == o._o; }
   bool operator!=(const oop& o) const  { return _o != o._o; }
 
-  bool operator==(nullptr_t) const     { return _o == nullptr; }
-  bool operator!=(nullptr_t) const     { return _o != nullptr; }
+  bool operator==(std::nullptr_t) const     { return _o == nullptr; }
+  bool operator!=(std::nullptr_t) const     { return _o != nullptr; }
 
   oop& operator=(const oop& o)         { _o = o._o; return *this; }
 };

src/hotspot/share/utilities/globalDefinitions.hpp

@@ -34,6 +34,8 @@
 
 #include COMPILER_HEADER(utilities/globalDefinitions)
 
+#include <cstddef>
+
 class oopDesc;
 
 // Defaults for macros that might be defined per compiler.