Summary:
This adds missing definitions for functions in the Lower directory
that were causing failures in shared library builds.
The definitions for these are taken from the fir-dev branch on github.
Reviewers: sscalpone, schweitz, jeanPerier, klausler
Reviewed By: schweitz
Subscribers: mgorny, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83771
David Truby