[llvm] [flang][runtime] Allow some list-directed child output to advance (PR #166847)

[Peter Klausler via llvm-commits]

klausler wrote:

> Right. It could be at other places where the array constructor is used. (Not limited to the `SOURCE=`).

Thanks for the confirmation.  In short, you want polymorphic array constructors that would work like anonymous polymorphic allocatables.  Does any Fortran compiler besides XLF support this feature?

https://github.com/llvm/llvm-project/pull/166847