build-sys: don't use nested BUILD_*

Signed-off-by: Karel Zak <kzak@redhat.com>
build-sys: don't use libs from pkg-config from libuser

Signed-off-by: Karel Zak <kzak@redhat.com>
build-sys: lslocks depends on libmount

Signed-off-by: Karel Zak <kzak@redhat.com>
build-sys: set dependence fdisk -> libfdisk -> libuuid

Signed-off-by: Karel Zak <kzak@redhat.com>
tests: add chfnsh build tests

Signed-off-by: Karel Zak <kzak@redhat.com>
tests: update build tests

 * remove ld-linux-* from output
 * findmnt linked with libudev
 * lslocks linked with libmount
 * uuidd linked with librt
 * static binaries are no more enabled by default
 * chfn/chsh linked with libuser
 * add nsenter, runuser, setpriv

Signed-off-by: Karel Zak <kzak@redhat.com>