perl backend: more reliable fullpath to Perl

Author: scivision

+stdlib/private/executable.pl

@@ -1 +1,11 @@
-print $^X;
+# https://perldoc.perl.org/variables/$%5EX
+# we do this instead of $^X to get a full reliable path to Perl
+
+use Config;
+my $secure_perl_path = $Config{perlpath};
+if ($^O ne 'VMS') {
+    $secure_perl_path .= $Config{_exe}
+    unless $secure_perl_path =~ m/$Config{_exe}$/i;
+}
+
+print $secure_perl_path