Backport 2.7: Use "#!/usr/bin/env perl" as shebang line.
diff --git a/tests/scripts/gen_ctr_drbg.pl b/tests/scripts/gen_ctr_drbg.pl
index 66d9b3a..08ca5df 100755
--- a/tests/scripts/gen_ctr_drbg.pl
+++ b/tests/scripts/gen_ctr_drbg.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # Based on NIST CTR_DRBG.rsp validation file
 # Only uses AES-256-CTR cases that use a Derivation function