Define WINDOWS in all Mingw32 cases.

util/pl/Mingw32.pl

@@ -17,7 +17,7 @@ $mkdir='gmkdir';
 
 $cc='gcc';
 if ($debug)
-	{ $cflags="-g2 -ggdb"; }
+	{ $cflags="-DL_ENDIAN -DWINDOWS -g2 -ggdb"; }
 else
 	{ $cflags="-DL_ENDIAN -DWINDOWS -fomit-frame-pointer -O3 -m486 -Wall"; }
 

util/pl/Mingw32f.pl

@@ -11,9 +11,9 @@ $rm='del';
 
 $cc='gcc';
 if ($debug)
-	{ $cflags="-g2 -ggdb"; }
+	{ $cflags="-DWINDOWS -g2 -ggdb"; }
 else
-	{ $cflags="-O3 -fomit-frame-pointer"; }
+	{ $cflags="-DWINDOWS -O3 -fomit-frame-pointer"; }
 
 $obj='.o';
 $ofile='-o ';