POSIX.pm

use v6; 

use NativeCall;

# I like Git's distinction between "porcelain" and "plumbing"
my module POSIXPlumbing {
}

class X::POSIX {
    submethod BUILD() {
        # XXX initialize from errno/strerror
    }   
}

module POSIX {
    our sub getuid() returns Int is native is export(:ALL) { ... }

    # XXX generate subs by name

}
our sub EXPORT(|) {
    # XXX do exporting
}

test.p6

use v6; 

use lib 'lib';
use POSIX <getuid>;

say getuid();