We really need compile _all_ sources for user target with -fpie when
use --enable-user-pie.

It's regression introduced by commit add16157.
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>