diff --git a/scripts/headerdep.pl b/scripts/headerdep.pl
index 97399da89ef..b7f6c560e24 100755
--- a/scripts/headerdep.pl
+++ b/scripts/headerdep.pl
@@ -19,7 +19,7 @@ my $opt_graph;
 	version	=> \&version,
 
 	all	=> \$opt_all,
-	I	=> \@opt_include,
+	"I=s"	=> \@opt_include,
 	graph	=> \$opt_graph,
 );