This patch implements noncontiguous "target update" for Fortran, on top
of the following in-review patch series:
https://gcc.gnu.org/pipermail/gcc-patches/2022-December/609031.html
(with followup:
https://gcc.gnu.org/pipermail/gcc-patches/2023-January/609566.html)
and:
https://gcc.gnu.org
This patch fixes several cases where multiple attach or detach mapping
nodes were being created for stand-alone attach or detach clauses
in Fortran. After the introduction of stricter checking later during
compilation, these extra nodes could cause ICEs, as seen in the PR.
The patch also fixes ca
