I know Perl doesn't have an #include directive.

Sure it does. the -P flag to perl runs the code through cpp first. Here's a quick example:

#!/usr/bin/perl -Pw
use strict;

#define CHOICE 1

print "Hey look! I'm",

#ifndef CHOICE
' not',
#endif

" using the C preprocessor.\n";

# Here is an example of #include.

my $passwd = <<'-PASSWD-';

#include "/etc/passwd"

-PASSWD-

print "Here is /etc/passwd: $passwd\n";
[download]

note -P can have problems distinguishing between preprocessor directives and perl comments. Also I don't know how well it works on non-Unix platforms where cpp might be missing. All in all it's a poor solution to your problem but it's there if you do need to us it.