diff --git a/build/autoconf/config.guess b/build/autoconf/config.guess
index c32d5488da7..dc37b18b0fd 100755
--- a/build/autoconf/config.guess
+++ b/build/autoconf/config.guess
@@ -738,6 +738,10 @@ EOF
     xx:WINNT:* | xx:WIN95:*)
 	echo i586-pc-msvc
 	exit 0 ;;
+# MKS Toolkit
+    [34567]86:Windows_NT:*)
+	echo i386-pc-mksnt
+	exit 0 ;;
 ###  End MozillaHack
     i*:PW*:*)
 	echo ${UNAME_MACHINE}-pc-pw32
diff --git a/build/autoconf/config.sub b/build/autoconf/config.sub
index 536e7a0e38b..b482629b69c 100755
--- a/build/autoconf/config.sub
+++ b/build/autoconf/config.sub
@@ -598,6 +598,10 @@ case $basic_machine in
 		basic_machine=i386-pc
 		os=-msvc
 		;;
+	i386-mksnt)
+		basic_machine=i386-pc
+		os=-mksnt
+		;;
 #### End MozillaHack 
 	miniframe)
 		basic_machine=m68000-convergent
@@ -1080,7 +1084,7 @@ case $os in
 	      | -cygwin* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
 	      | -mingw32* | -linux-gnu* | -uxpv* | -beos* | -mpeix* | -udk* \
 	      | -interix* | -uwin* | -rhapsody* | -darwin* | -opened* \
-	      | -msvc* \
+	      | -msvc* | -mksnt* \
 	      | -openstep* | -oskit* | -conix* | -pw32* | -nonstopux* \
 	      | -storm-chaos* | -tops10* | -tenex* | -tops20* | -its* \
 	      | -os2* | -vos*)