Fix: [Win32] WIN32 may not be defined, always prefer the compiler predefined macro _WIN32

src/stdafx.h

@@ -167,7 +167,7 @@
 	#include <malloc.h> // alloca()
 #endif
 
-#if defined(WIN32)
+#if defined(_WIN32)
 	#define WIN32_LEAN_AND_MEAN     // Exclude rarely-used stuff from Windows headers
 #endif
 
@@ -232,18 +232,18 @@
 		#define FALLTHROUGH
 	#endif
 
-	#if defined(WIN32) && !defined(_WIN64) && !defined(WIN64)
+#	if defined(_WIN32) && !defined(_WIN64)
 		#if !defined(_W64)
 			#define _W64
 		#endif
 
 		typedef _W64 int INT_PTR, *PINT_PTR;
 		typedef _W64 unsigned int UINT_PTR, *PUINT_PTR;
-	#endif /* WIN32 && !_WIN64 && !WIN64 */
+#	endif /* _WIN32 && !_WIN64 */
 
-	#if defined(_WIN64) || defined(WIN64)
+#	if defined(_WIN64)
 		#define fseek _fseeki64
-	#endif /* _WIN64 || WIN64 */
+#	endif /* _WIN64 */
 
 	/* zlib from vcpkg use cdecl calling convention without enforcing it in the headers */
 #	if defined(WITH_ZLIB)
@@ -281,7 +281,7 @@
 /* NOTE: the string returned by these functions is only valid until the next
  * call to the same function and is not thread- or reentrancy-safe */
 #if !defined(STRGEN) && !defined(SETTINGSGEN)
-	#if defined(WIN32) || defined(WIN64)
+#	if defined(_WIN32)
 		char *getcwd(char *buf, size_t size);
 		#include <tchar.h>
 		#include <io.h>
@@ -292,14 +292,14 @@
 
 		const char *FS2OTTD(const TCHAR *name);
 		const TCHAR *OTTD2FS(const char *name, bool console_cp = false);
-	#else
+#	else
 		#define fopen(file, mode) fopen(OTTD2FS(file), mode)
 		const char *FS2OTTD(const char *name);
 		const char *OTTD2FS(const char *name);
-	#endif /* WIN32 */
+#	endif /* _WIN32 */
 #endif /* STRGEN || SETTINGSGEN */
 
-#if defined(WIN32) || defined(WIN64) || defined(__OS2__) && !defined(__INNOTEK_LIBC__)
+#if defined(_WIN32) || defined(__OS2__) && !defined(__INNOTEK_LIBC__)
 	#define PATHSEP "\\"
 	#define PATHSEPCHAR '\\'
 #else