The NPTL add-on has always been internal, so there is no
reason to try downloading it, it will never succeed.
Add provision to skip other add-ons as well.
For consistency, do the same test in both glibc and eglibc.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
1 This is NOT the official version of dialog. This version has been
2 significantly modified from the original. It is for use by the Linux
3 kernel configuration script. Please do not bother Savio Lam with