WANT_PHP_WEB is just a synonym for WANT_PHP_CGI in automated build environments

[Matthew Pounsett]

It looks to me like the rules that WANT_PHP_WEB uses to decide whether to build the CGI or module version of PHP will always choose the CGI version unless the module is already installed.  If this is true, it means that in automated build environments (e.g. tinderbox) – where *only* the direct dependencies of a port are installed at build time – there isn’t any way to tell WANT_PHP_WEB to install the module.  This effectively makes WANT_PHP_WEB a synonym for WANT_PHP_CGI in these environments.

Have I missed something, or is this a significant flaw in the design of the WANT_PHP_{WEB,CGI,MOD} knobs?  

It seems to me that this should be changed in one of three ways:
1) It should be possible to provide direction to WANT_PHP_WEB via some make.conf knob
2) WANT_PHP_WEB should be removed, and WANT_PHP_{CGI,MOD} should always be chosen using a radio selector at config time, or by setting in make.conf
3) WANT_PHP_WEB should cause a radio button selector to appear at port config time

(3) seems like the least desirable, since it leaves no way to provide direction in a batch mode build.  I think my preference would be for (2).

Does anyone have any other ideas for how to improve this?  Or any pointers to a way that already exists to provide direction to the ports system about whether WANT_PHP_WEB should imply _CGI or _MOD?