[Bug fortran/82143] New: add a -fdefault-real-16 flag

[janus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82143

            Bug ID: 82143
           Summary: add a -fdefault-real-16 flag
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: janus at gcc dot gnu.org
  Target Milestone: ---

gfortran currently knows the options -fdefault-real-8 and -fdefault-double-8.

It would be useful to add an -fdefault-real-16 (corresponding to ifort's
-real-size 128) and maybe also -fdefault-double-16.

For completeness, also -fdefault-real-4 might be worth adding (which would
correspond to the current default behavior).