[clang] [flang] [Flang][Driver] Add -print-resource-dir command line flag to emit Flang's resource directory (PR #90886)

[Michael Klemm via cfe-commits]

mjklemm wrote:

> How does this compare to GFortran and Classic Flang? Anything resembling this flag?

GFortran does not have it, but Classic Flang does.  So, it's closing a gap to Classic Flang here as well.

https://github.com/llvm/llvm-project/pull/90886