gallium/swr: add option for static link

Set swr-shared to 'false' to link SWR statically into Mesa.
Only one swr arch can be specified if swr-shared is set to false.

Reviewed-by: Jan Zielinski <jan.zielinski@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3510>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3510>
3 files changed