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

[Kelvin Li via cfe-commits]

kkwli wrote:

> LLVM Buildbot has detected a new failure on builder `ppc64le-flang-rhel-clang` running on `ppc64le-flang-rhel-test` while building `clang,flang-rt,flang` at step 3 "clean-build-dir".
> 
> Full details are available at: https://lab.llvm.org/buildbot/#/builders/157/builds/45154
> Here is the relevant piece of the build log for the reference

PR https://github.com/llvm/llvm-project/pull/185699

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