Draft 3 of IEEE 1003.1 200x, "2.2 The Compilation Environment"

  All identifiers that begin with an underscore and either an uppercase
  letter or another underscore are always reserved for any use by the
  implementation.

Remove mostly all references to APACHE and CGI_BINARY from the code.

- Apache include files are no longer included by any PHP code, except for the Apache SAPI module.
- No server specific code is in any of the base PHP code.

Still left to be done:
- Eliminate any references to APACHE from the few remaining modules.
- Move request_info.c's logic to SAPI
- Modify the regex function names, and globals, so that we can always
  include them, without having to fear any interference with Apache;
  Always use the bundled regex library

(otherwise php_reg* would not be prototyped)

system, apache, or php's regex library by using the --with-regex option.
"php" is the default; if you use --with-apache in combination with
Apache 1.3.x, the default is "apache".

and php_regex.h figures out which regex header files to include and
defines symbols that prevents other stuff from including the wrong versions
of regex header files.