Closed requested to merge wip/unloading into master
This folds in @osa1's object unloading patch, !3478 (closed), and an adaptation of @niteria's dynamic object unloading work.
Note that unloading of dynamic objects currently only works on
glibc since it relies on its
dl_iterate_phdr interface to traverse the loaded object's segments.
Fixes #16525 (closed).