use 5.012;
use warnings;

use File::Spec;

my ($sep, $exe) = do {
  if ($^O =~ /^MSWin/) {
    (';', '.exe')
  }
  else {
    (':', '')
  }
};

sub findgs {
  for my $dir (split $sep, $ENV{PATH}) {
    my $_ = File::Spec->catfile($dir, "gs$exe");
    return $_ if -x;
  }
}

if (my $gs = findgs) {
  say "ghostscript found: $gs";
}
else {
  warn "ghostscript not found";
}