Use "#!/usr/bin/env perl" as shebang line.
diff --git a/scripts/config.pl b/scripts/config.pl
index 5bf2785..468aeb9 100755
--- a/scripts/config.pl
+++ b/scripts/config.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # This file is part of mbed TLS (https://tls.mbed.org)
 #