Misc fixes

Here's a few bits and pieces.

1. Don't enable -g by default
2. A patch from Gentoo that may or may not be of interest
3. Make tests run properly when chroot does not live in /usr/sbin

Note that while the last commit lets me *run* tests, one still fails:

    1..8
    ok 1 chroot test-chroot / / (not escaped): 2333653 / 2333653 /
    ok 2 chroot test-chroot / . (not escaped): 2333653 / 2333653 /
    ok 3 chroot test-chroot . / (not escaped): 2333653 / 2333653 /
    not ok 4 chroot test-chroot . . (escaped): 2333653 / 2333653 /
    ok 5 fakechroot test-chroot / / (not escaped): 2333653 / 2333653 /
    ok 6 fakechroot test-chroot / . (not escaped): 2333653 / 2333653 /
    ok 7 fakechroot test-chroot . / (not escaped): 2333653 / 2333653 /
    ok 8 fakechroot test-chroot . . (escaped): 2333653 / 2333530 /
    FAIL: t/escape-nested-chroot.t