Add pic variant to cflags in boost. (#9750)
Add pic variant to cflags in boost. (#9750)

* Add pic variant to cflags in boost.

* Improve description in pic variant of boost, see #9750.

iulian787/spack,LLNL/spack,iulian787/spack,iulian787/spack,iulian787/spack,LLNL/spack,LLNL/spack,iulian787/spack,LLNL/spack,LLNL/spack