Use the unversioned subdirectory in the rpath.

While we use versioned subdirectory triples for Swift module paths, this
part of the rpath should be unversioned, if at the very least, for
consistency.

While we are here, ensure that -z origin is used when linking, which is
necessary for ORIGIN processing.

Author: 3405691582

Utilities/build-script-helper.py

@@ -110,6 +110,11 @@ def get_swiftpm_options(args):
       swiftpm_args += [
         '-Xlinker', '-rpath', '-Xlinker', '$ORIGIN/../lib/swift/freebsd',
       ]
+    elif '-openbsd' in args.build_target:
+      swiftpm_args += [
+        '-Xlinker', '-rpath', '-Xlinker', '$ORIGIN/../lib/swift/openbsd',
+        '-Xlinker', '-z', '-Xlinker', 'origin',
+      ]
     else:
       # Library rpath for swift, dispatch, Foundation, etc. when installing
       swiftpm_args += [