[clang] [flang] [llvm] [openmp] [Flang] Move builtin .mod generation into runtimes (PR #137828)

[Jan Patrick Lehr via llvm-commits]

jplehr wrote:

We see this breaking our buildbot in https://lab.llvm.org/staging/#/builders/105/builds/37275

I'm going to open a revert PR.

https://github.com/llvm/llvm-project/pull/137828