diff --git a/libio/configure.in b/libio/configure.in
index 9d523e7898b..ef19da09f48 100644
--- a/libio/configure.in
+++ b/libio/configure.in
@@ -142,7 +142,7 @@ fi
 if [ -n "${with_cross_host}" ] ; then
     rm -f Makefile.tem
     sed \
-	-e 's|INSTALLDIR.*=.*$|INSTALLDIR = $(tooldir)/lib|' \
+	-e 's|\(^[ 	]*INSTALLDIR[ 	]*=[ 	]*\)[^ 	;]*|\1$(tooldir)/lib|' \
 	Makefile >Makefile.tem
     mv -f Makefile.tem Makefile
 fi