Fix PyTorch3D build failure on windows

Summary: Replace #defines by typedefs by following the instructions at #1970

Reviewed By: bottler

Differential Revision: D75083182

fbshipit-source-id: 7131fe555bb0da615b341e77ddd8761ebce9d7eb

Author: Ting Xu

pytorch3d/csrc/pulsar/global.h

@@ -15,8 +15,8 @@
 #endif
 
 #if defined(_WIN64) || defined(_WIN32)
-#define uint unsigned int
-#define ushort unsigned short
+using uint = unsigned int;
+using ushort = unsigned short;
 #endif
 
 #include "./logging.h" // <- include before torch/extension.h