--- a/config/config.sub
+++ b/config/config.sub
@@ -380,6 +380,9 @@ case $basic_machine in
 	amd64)
 		basic_machine=x86_64-pc
 		;;
+	amd64-*)
+		basic_machine=x86_64-`echo $basic_machine | sed 's/^[^-]*-//'`
+		;;
 	amdahl)
 		basic_machine=580-amdahl
 		os=-sysv
