Swift: support SONAME on ELFish targets

We should enable the soname to be setup for ELF shared libraries. Failure to do so generates binaries with incorrect names which prevents loading.

Do: test

added workflow:in-review label

changed milestone to %3.16.0

assigned to @brad.king

This merge request has been queued for testing. Test results may be viewed on:

• CDash (master)
• Buildbot (master) (only visible from inside Kitware)

Branch-at-master: 6af97178

added lang:swift label

Do: stage

added workflow:nightly-testing label and removed workflow:in-review label

Do: merge

removed workflow:nightly-testing label

merged

mentioned in commit 1b8fdad2