After reading the forums, I figured out how to include runtime modules based on specific operating systems. Right now I have something like this 
my $OS                  = $^O;
if ($OS =~ m/win32/i)  {
    eval "use Win32::File";
    eval "use Win32::FileSecurity";
}
if ($OS =~ /darwin/) {
    do something else
}
if ($OS =~ m/win32/i) {
    my $attrib;
    Win32::File::GetAttributes($http_rec_localdir, $attrib);
    if ($attrib & (Win32::File::SYSTEM | Win32::File::HIDDEN)) {
        &error_dialog( "Destination Directory",
               "Destination directory is not writable." );
        return;
    }
}

[download]
The code compiles fine on windows however on Mac, it fails since Win32::File was not included. The message for failure

"Bareword 'Win32::File::SYSTEM' not allowed while 'strict subs' in use at ...."

Can someone suggest a solution. Much appreciated

In reply to including modules during runtime and dealing with OS specific (constants) code block by periferral

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