diff --git a/configure b/configure
index 6a1e859..a8b014a 100755
--- a/configure
+++ b/configure
@@ -8705,7 +8705,7 @@ cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 
-			    #ifdef __WIN32__
+			    #ifdef _WIN32
 				#error cross-compiler
 			    #endif
 
diff --git a/tools/genStubs.tcl b/tools/genStubs.tcl
index 77d0b51..5aa5ecf 100644
--- a/tools/genStubs.tcl
+++ b/tools/genStubs.tcl
@@ -268,10 +268,10 @@ proc genStubs::rewriteFile {file text} {
 proc genStubs::addPlatformGuard {plat text} {
     switch $plat {
 	win {
-	    return "#ifdef __WIN32__\n${text}#endif /* __WIN32__ */\n"
+	    return "#ifdef _WIN32\n${text}#endif /* _WIN32 */\n"
 	}
 	unix {
-	    return "#if !defined(__WIN32__) /* UNIX */\n${text}#endif /* UNIX */\n"
+	    return "#if !defined(_WIN32) /* UNIX */\n${text}#endif /* UNIX */\n"
 	}		    
 	macosx {
 	    return "#ifdef MAC_OSX_TCL\n${text}#endif /* MAC_OSX_TCL */\n"
@@ -280,7 +280,7 @@ proc genStubs::addPlatformGuard {plat text} {
 	    return "#ifdef MAC_OSX_TK\n${text}#endif /* MAC_OSX_TK */\n"
 	}
 	x11 {
-	    return "#if !(defined(__WIN32__) || defined(MAC_OSX_TK)) /* X11 */\n${text}#endif /* X11 */\n"
+	    return "#if !(defined(_WIN32) || defined(MAC_OSX_TK)) /* X11 */\n${text}#endif /* X11 */\n"
 	}
     }
     return "$text"
diff --git a/win/makefile.vc b/win/makefile.vc
index 0b061a1..578c033 100644
--- a/win/makefile.vc
+++ b/win/makefile.vc
@@ -431,7 +431,7 @@ $<
 <<
 
 {$(WINDIR)}.rc{$(TMP_DIR)}.res:
-	$(rc32) -fo $@ -r -i "$(GENERICDIR)" -D__WIN32__ \
+	$(rc32) -fo $@ -r -i "$(GENERICDIR)" -D_WIN32 -D__WIN32__ \
 		-DCOMMAVERSION=$(DOTVERSION:.=,),0 \
 		-DDOTVERSION=\"$(DOTVERSION)\" \
 		-DVERSION=\"$(VERSION)$(SUFX)\" \