[bug#27461] [PATCH v2 1/2] gnu: Add z3.

[Danny Milosavljevic]

z3 fails to build on ARMHF, see <http://hydra.gnu.org/build/2204789/nixlog/1>.

>ld: api/dll/mem_initializer.o: relocation R_ARM_THM_MOVW_ABS_NC against `a 
>local symbol' can not be used when making a shared object; recompile with 
>-fPIC.

There's https://github.com/Z3Prover/z3/issues/585 which says essentially that 
one should use "cmake", then the problem doesn't appear.