anchor.diff:  
     interface
       subroutine mincf_free(cfg) &
  -      & bind(C,name='mincf_free')
  +          & bind(C,name='mincf_free')
         use iso_c_binding
         import :: config
         type(config), intent(inout) :: cfg
  
positive.code: 
      if ( present(errno) ) then
        call c_mincf_get(cfg, &
        & key, len(key,c_size_t), &
        & buf, len(buf,c_size_t), &
        & errno)
      else
        call c_mincf_get(cfg, &
        & key, len(key,c_size_t), &
        & buf, len(buf,c_size_t), &
        & errno_local)
        if ( errno_local .ne. 0 ) then
          call mincf_free(cfg)
          error stop "confort: fatal error while reading the configuration"
  
negative.code:         integer(c_int), intent(out) :: errno
        end subroutine
      end interface
  
      call c_mincf_get_default(cfg, &
          & key, len(key,c_size_t), &
          & buf, len(buf,c_size_t), &
          & defvalue, len(defvalue,c_size_t), &
          & errno_local)
  
      if ( present(errno) ) then
        errno = errno_local
      end if
    end subroutine
  
    !---------------------------------------------------------------------------!
  
    subroutine mincf_print_error(errno,file,line)
      integer, intent(in) :: errno
  