use warnings;
use strict;
 
use ExtUtils::MakeMaker;
use version;
 
my $min_wpi_ver = 2.36;
 
if (! -f '/usr/include/wiringPi.h' && ! -f '/usr/local/include/wiringPi.h'){
    print "wiringPi is not installed, exiting...\n";
    exit;
}
 
if (my $path = (grep { -x "$_/gpio" } split /:/, $ENV{PATH})[0]){
    my $bin = "$path/gpio";
    my $gpio_info = `$bin -v`;
 
    if (my ($version) = $gpio_info =~ /version:\s+(\d+\.\d+)/){
 
        my $installed_ver = version->parse($version);
 
        if ($installed_ver < $min_wpi_ver){
            print "\nyou must have wiringPi version $min_wpi_ver" .
                  " or greater installed to continue.\n\n" .
                  "You have version $version\n";
            exit;
        }
    }
}
else {
    print "\ncan not determine wiringPi version. Ensure version ${min_wpi_ver}+ " .
          " is installed. Can't continue\n";
    exit;
}
...