[clang] [flang] [llvm] [flang] Add runtime trampoline pool for W^X compliance (PR #183108)

[Sairudra More via cfe-commits]

Saieiei wrote:

> One last minor point: the commit message talks about `W^X` compliance, but it's really about `!(W&X)`. `W^X` can be zero so long as both W and X are.

The commit message has been updated

https://github.com/llvm/llvm-project/pull/183108