Defined I/O subroutines have UNIT= and IOSTAT= dummy arguments that are
required to have type INTEGER with its default kind. When that default
kind is modified via -fdefault-integer-8, calls to defined I/O
subroutines from the runtime don't work.
Add a flag to the two data structures shared between the compiler and
the runtime support library to indicate that a defined I/O subroutine
was compiled under -fdefault-integer-8. This has been done in a
compatible manner, so that existing binaries are compatible with the new
library and new binaries are compatible with the old library, unless of
course -fdefault-integer-8 is used.
Fixes https://github.com/llvm/llvm-project/issues/148638.
52a46dc57f