gbuild: Allow to use more components in one library.

It probably does not make much sense in general but will be used to
optionally disable some implementations in a library.

Change-Id: Ib491b8b642907b5bb20d458cbf766c9c9a5a5111
gbuild: fix check for registered libraries

Change-Id: I0e8524a0933114196a80317b9a427d8cd3f3e459
sccomp_lpsolver does not need to link against sc

Change-Id: I47a758fbcfcefc2bdd1cdbb89ef219a7ebb2af47
sccomp: Share common code and have only one library.

And use constructor feature for UNO implementations.

Change-Id: I42b6a6f417049cc8e2d44b74c7adc552680b1f2d