[PATCH 37/42] add pocl_get_distro_cpu_name()

[PATCH 37/42] add pocl_get_distro_cpu_name()

in distro builds, map each kernellib_name to a specific llvm_cpu
which is then used as compilation target instead of the native cpu

this limits the possible code generation targets in distro builds
in order to be able to run tests against all of them with a minimal
number of different (physical) CPU models

Gbp-Pq: Name 0037-add-pocl_get_distro_cpu_name.patch