Swift 5.8 doesn’t reliably build with Ninja 1.12, and apparently
neither do old versions of ROCm, due to a build scheduling change
breaking builds with undeclared dependencies. Upstream Swift have
pinned 1.11 for now.
Reintroducing it isn’t a good long‐term solution, but seems
like the easiest way to avoid shipping 24.11 with a broken Swift
on Darwin. The patch for 32‐bit systems has not been restored,
as Swift doesn’t support them anyway.
The previously used pattern was introduced in #318614, but technically
leaked the default flags into the global scope. While this would
probably not make much of a practical difference, making concatTo
support default values is a much cleaner approach.
