[Bug fortran/69064] Unhelpful error message when a module variable was not included in the only list

[kottinge at utk dot edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69064

--- Comment #35 from kottinge at utk dot edu ---
read_input_mod is built from the source file read_input_mod.f90.  It's the one
with the bug