[Bug fortran/100651] [11/12/13/14 Regression] Bad handling of optional, allocatable character argument

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100651

--- Comment #12 from anlauf at gcc dot gnu.org ---
Created attachment 56690
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56690&action=edit
Draft patch

Very rough patch that fixes this PR and also pr93762.
Need more thorough testing.