write_log() does not call write_file(), why not?

[eluser]sophistry[/eluser]
so, i found this in the changelog today:

"Added is_really_writable() to Common.php to provide a cross-platform reliable method of testing file/folder writability."

so, the devs *will* move functions into Common.php but more readily for cross-platform usage. it makes sense to have write_file() be moved into common.php also (for the reasons why is_really_writeable() was moved in there). then, everyone will have a standard way of writing files just like they have a standard (portable) way of checking file_writeable staus and active record for using dbs, etc...