Remove redundant tests for __WIN32__ in wxMSW code.

This is always defined, Win16 is not supported since ages and Win64 defines
both __WIN32__ and __WIN64__.

include/wx/msw/ole/uuid.h

@@ -20,7 +20,6 @@
 
 // ----- taken from RPC.H
 #ifndef UUID_DEFINED            // in some cases RPC.H will be already
-  #ifdef  __WIN32__             // included, so avoid redefinition
     typedef struct
     {
       unsigned long   Data1;
@@ -28,7 +27,6 @@
       unsigned short  Data3;
       unsigned char   Data4[8];
     } UUID;                     // UUID = GUID = CLSID = LIBID = IID
-  #endif  // WIN32
 #endif  // UUID_DEFINED
 
 #ifndef GUID_DEFINED