Use _WIN32 to check for windows, not WIN32

These should have been fixed in #24259 but must have been missed.
diff --git a/goo/gfile.cc b/goo/gfile.cc
index 6b98ec2..642f396 100644
--- a/goo/gfile.cc
+++ b/goo/gfile.cc
@@ -423,7 +423,7 @@
 #endif
 }
 
-#ifdef WIN32
+#ifdef _WIN32
 GooString *fileNameToUTF8(char *path) {
   GooString *s;
   char *p;
@@ -462,7 +462,7 @@
 #endif
 
 FILE *openFile(const char *path, const char *mode) {
-#ifdef WIN32
+#ifdef _WIN32
   OSVERSIONINFO version;
   wchar_t wPath[_MAX_PATH + 1];
   char nPath[_MAX_PATH + 1];
diff --git a/goo/gfile.h b/goo/gfile.h
index be53994..0929f7e 100644
--- a/goo/gfile.h
+++ b/goo/gfile.h
@@ -105,7 +105,7 @@
 // should be "w" or "wb".  Returns true on success.
 extern GBool openTempFile(GooString **name, FILE **f, const char *mode);
 
-#ifdef WIN32
+#ifdef _WIN32
 // Convert a file name from Latin-1 to UTF-8.
 extern GooString *fileNameToUTF8(char *path);
 
diff --git a/poppler/GlobalParams.cc b/poppler/GlobalParams.cc
index 2a7e56b..2ba23ec 100644
--- a/poppler/GlobalParams.cc
+++ b/poppler/GlobalParams.cc
@@ -253,7 +253,7 @@
   ~SysFontList();
   SysFontInfo *find(GooString *name, GBool isFixedWidth, GBool exact);
 
-#ifdef WIN32
+#ifdef _WIN32
   void scanWindowsFonts(GooString *winFontDir);
 #endif
 #ifdef WITH_FONTCONFIGURATION_FONTCONFIG
@@ -261,7 +261,7 @@
 #endif
 private:
 
-#ifdef WIN32
+#ifdef _WIN32
   SysFontInfo *makeWindowsFont(char *name, int fontNum,
 			       char *path);
 #endif
diff --git a/splash/SplashMath.h b/splash/SplashMath.h
index a56bd12..8b3b504 100644
--- a/splash/SplashMath.h
+++ b/splash/SplashMath.h
@@ -64,7 +64,7 @@
 		   : "=m" (oldCW), "=m" (newCW), "=m" (result), "=r" (t)
 		   : "m" (x));
     return result;
-#elif defined(WIN32) && defined(_M_IX86)
+#elif defined(_WIN32) && defined(_M_IX86)
     // floor() and (int)() are implemented separately, which results
     // in changing the FPCW multiple times - so we optimize it with
     // some inline assembly
@@ -111,7 +111,7 @@
 		   : "=m" (oldCW), "=m" (newCW), "=m" (result), "=r" (t)
 		   : "m" (x));
   return result;
-#elif defined(WIN32) && defined(_M_IX86)
+#elif defined(_WIN32) && defined(_M_IX86)
   // ceil() and (int)() are implemented separately, which results
   // in changing the FPCW multiple times - so we optimize it with
   // some inline assembly
@@ -156,7 +156,7 @@
 		   : "=m" (oldCW), "=m" (newCW), "=m" (result), "=r" (t)
 		   : "m" (x));
   return result;
-#elif defined(WIN32) && defined(_M_IX86)
+#elif defined(_WIN32) && defined(_M_IX86)
   // this could use round-to-nearest mode and avoid the "+0.5",
   // but that produces slightly different results (because i+0.5
   // sometimes rounds up and sometimes down using the even rule)