[libc++][PSTL] Remove current integration

We decided to go a different route. To make the switch easier, rip out the old integration first and build on a clean base.

Reviewed By: ldionne, #libc, #libc_abi

Spies: arichardson, libcxx-commits

Differential Revision: https://reviews.llvm.org/D148480

GitOrigin-RevId: 7d98590b3a23645584779a1036d319082f3be7c9
1 file changed