[llvm] [BOLT][WIP] Support restartable sequences in tcmalloc (PR #157774)

[Maksim Panchenko via llvm-commits]

maksfb wrote:

For non-pie, we rely on linker's `--emit-relocs` to detect code pointers.

Let me take another look at the warnings.

https://github.com/llvm/llvm-project/pull/157774