mapserver.h: check _WIN32 instead of WIN32

The canonical macro is _WIN32.  WIN32 usually exists as well, but is a
non-standard macro.

See https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros?view=msvc-160

mapregex.h

@@ -36,7 +36,7 @@ extern "C" {
 
   /* We want these to match the POSIX standard, so we need these*/
   /* === regex2.h === */
-#ifdef WIN32
+#ifdef _WIN32
 #define MS_API_EXPORT(type)  __declspec(dllexport) type __stdcall
 #elif defined(__GNUC__) && __GNUC__ >= 4
 #define MS_API_EXPORT(type)  __attribute__ ((visibility("default"))) type

mapscript/mapscript.i

@@ -66,7 +66,7 @@
 #include "../../mapprimitive.h"
 #include "../../mapshape.h"
 
-#if defined(WIN32) && defined(SWIGCSHARP)
+#if defined(_WIN32) && defined(SWIGCSHARP)
 /* <windows.h> is needed for GetExceptionCode() for unhandled exception */
 #include <windows.h>
 #endif

mapserv.c

@@ -45,7 +45,7 @@
 
 #include "cpl_conv.h"
 
-#ifndef WIN32
+#ifndef _WIN32
 #include <signal.h>
 #endif
 
@@ -56,15 +56,15 @@
 
 static int finish_process = 0;
 
-#ifndef WIN32
+#ifndef _WIN32
 static void msCleanupOnSignal( int nInData )
 {
   (void)nInData;
   finish_process = 1;
 }
 #endif
 
-#ifdef WIN32
+#ifdef _WIN32
 static void msCleanupOnExit( void )
 {
   finish_process = 1;
@@ -237,7 +237,7 @@ int main(int argc, char *argv[])
   /* -------------------------------------------------------------------- */
   /*      Setup cleanup magic, mainly for FastCGI case.                   */
   /* -------------------------------------------------------------------- */
-#ifndef WIN32
+#ifndef _WIN32
   signal( SIGUSR1, msCleanupOnSignal );
   signal( SIGTERM, msCleanupOnSignal );
 #endif

mapserver.h

@@ -148,15 +148,15 @@ typedef const ms_uint32 *ms_const_bitarray;
 /* EQUAL and EQUALN are defined in cpl_port.h, so add them in here if ogr was not included */
 
 #ifndef EQUAL
-#if defined(WIN32) || defined(WIN32CE)
+#if defined(_WIN32) || defined(WIN32CE)
 #  define EQUAL(a,b)              (stricmp(a,b)==0)
 #else
 #  define EQUAL(a,b)              (strcasecmp(a,b)==0)
 #endif
 #endif
 
 #ifndef EQUALN
-#if defined(WIN32) || defined(WIN32CE)
+#if defined(_WIN32) || defined(WIN32CE)
 #  define EQUALN(a,b,n)           (strnicmp(a,b,n)==0)
 #else
 #  define EQUALN(a,b,n)           (strncasecmp(a,b,n)==0)

mapwms.cpp

@@ -53,7 +53,7 @@
 #include <string>
 #include <vector>
 
-#ifdef WIN32
+#ifdef _WIN32
 #include <process.h>
 #endif