diff --git a/config.sub b/config.sub
index f208366..0f5419a 100755
--- a/config.sub
+++ b/config.sub
@@ -106,6 +106,9 @@ case $os in
 	-ptx*)
 		basic_machine=`echo $1 | sed -e 's/86-.*/86-sequent/'`
 		;;
+	-windowsnt*)
+		os=`echo $os | sed -e 's/windowsnt/winnt/'`
+		;;
 esac
 
 # Decode aliases for certain CPU-COMPANY combinations.
@@ -566,7 +569,7 @@ case $os in
 	      | -riscos* | -linux* | -uniplus* | -iris* | -rtu* | -xenix* \
 	      | -hiux* | -386bsd* | -netbsd* | -freebsd* | -riscix* \
 	      | -lynxos* | -bosx* | -nextstep* | -cxux* | -aout* | -elf* \
-	      | -ptx* | -coff*)
+	      | -ptx* | -coff* | -winnt*)
 		;;
 	-sunos5*)
 		os=`echo $os | sed -e 's|sunos5|solaris2|'`