fix build error with musl libc due to if_slip.h

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
tar: fix tar -T to add entries in the exact order as the input list

This fixes tar to order files in tarball correctly in this case:

$ touch 1 2 3; echo -e '1\n2\n3' | tar -T- -c | tar t
1
2
3

Signed-off-by: SASAKI Suguru <suguru@sonik.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>