[compiler-rt] [compiler-rt] Add CMake option to enable execute-only code generation on AArch64 (PR #140555)

[Csanád Hajdú via llvm-commits]

Il-Capitano wrote:

> Part of the change does impact a place where there was no use of the macro and we placed text into `.section __TEXT,__text` which is the proper spelling.

Is there a meaningful difference between `.text` and `.section __TEXT,__text`? From what I found, and my local testing, the former is an alias of the latter. There are instances in compiler-rt, where `.text` is used on MachO as well (e.g. `compiler-rt/lib/orc/sysv_reenter.arm64.S`).

> Right, that is what I was thinking. For static linking, that might also enable DCE, which can be a benefit.

This is an orthogonal change to mine though. Would you be fine with merging this PR as is, and you/someone else preparing a separate patch for that? Alternatively that change could be done first, and I'd be happy to do a rebase on this PR accommodating those changes.

https://github.com/llvm/llvm-project/pull/140555