[git tag svn_nptl] install_headers.sh: make more user friendly

[Mike Frysinger]

commit: http://git.uclibc.org/uClibc/commit/?id=9bd43a50fea3a12355d400fccf2328a2b492c526
branch: http://git.uclibc.org/uClibc/commit/?id=refs/tags/svn_nptl

Make it easier to run this by hand and don't abort when recursive chown
and chmod fail as these often aren't due to uClibc settings.

Signed-off-by: Mike Frysinger <vapier at gentoo.org>
Signed-off-by: Austin Foxley <austinf at cetoncorp.com>

this is a tag, so no patch shown