[DOC] proto void header_remove([string header_name])
      Removes an HTTP header previously set using header()
      The header_name parameter is optionnal, all headers are
      removed if it is not set

[SAPIs] The header_handler callback in sapi_module_struct has
           been changed, it now take a new argument.

           When it is set to SAPI_HEADER_DELETE, sapi_header->header is
           the name of an header, header_handler has to delete it.

           When it is set to SAPI_HEADER_DELETE_ALL, header_handler has
           to delete all headers.

           When sapi_header_op_enum is SAPI_HEADER_ADD or _REPLACE,
           sapi_header->header is in the form "Name: value", header_handler
           has to add or replace the given header.

           In all cases, header_handler must not free sapi_header or
           sapi_header->header. SAPI_HEADER_ADD must be returned if the
           header has been added or replaced, or 0 in other cases.

After the sigsetjmp change, this is patch #2 in an effort to get some
sanity restored to signal handling in PHP.

This patch does two things.  First, it makes it possible to reset the
timeout without resetting the signal handlers.  This is important for
cases where an extension may have deferred signals in its MINIT in order
to implement critical sections. It also lays the groundwork for cleaning
up our signal handling and perhaps eventually implementing our own
signal deferring mechanism so we can have true critical sections.

The second thing this does is to make it possible to terminate the current
child process (only for Apache1 at the moment) on a timeout.  There are
a number of extensions that are unhappy about being longjmp'ed out of
and when this happens on a timeout they are left in an inconsistent state.
By turning on exit_on_timeout you can now force the process to terminate
on a timeout which will clean up any hanging locks and/or memory left
hanging after the longjmp.

Never mind, it looks like ext/filter does an estrdup on everything it
gets which doesn't seem very efficient to me as most things it gets
passed will already be emalloc'ed.  My custom version of the filter
extension doesn't do this which led to the confusion.