Hi,

These two (independent) patches add two tiny Fortran 2023 features: new ISO_FORTRAN_ENV named constants and SELECTED_LOGICAL_KIND intrinsic.

Bootstrapped and regtested on x86_64-pc-linux-gnu.
Please review, and let me know if it’s okay to push once we’re back in stage 1.
(I know it’s not particularly soon, but I don’t want to forget these so I’m posting them for review)

FX