my $module = $^O =~ /MSWin32/ ? "Win32::Foo" : "Unix::Bar";
# /win/ will make Darwin (OSX) users unhappy :-)

eval "use $module"
  or die "$module didn't return a true value";
die $@ if $@;

##</code><code>##

BEGIN{
  if ($^O =~ /MSWin32/) {
    require Win32::Foo;
    Win32::Foo->import();
  } else {
    require Unix::Bar;
    Unix::Bar->import();
  };
};

##</code><code>##

use UNIVERSAL::require;
my $module = $^O =~ /MSWin32/ ? "Win32::Foo" : "Unix::Bar";

$module->require;
$module->import(1,2,3);

##</code><code>##

BEGIN {
  my $module = $^O =~ /MSWin32/ ? "Win32::Foo" : "Unix::Bar";

  my $file = $module . ".pm";
  $file =~ s!::!/!g;

  require $file
    or die "$file didn't return a true value";

  $module->import();
};