php 5.2.4 disable mail() function

[Hartmut Wernisch <hw@xxxxxxxxxxxxxxxx>]

Is there a patch available to revert the "Changed mail() function to be
always available. (Johannes)" (see changelog)?

I'am looking for an easy way to disable the build in mail-function again.
I would prefer not to diff the old and new sources, so any other idea? :)

Thanks in advance,
Hartmut