php-cgi can take a few parameters, such as

--php-ini path|file
-c path|file   Look for php.ini file in the directory path or use the specified file

to read an entire php.ini from somewhere else (we could allow people to have a copied/changed php.ini in their home dir

or we can add a --php-debug parameter that uses

--define foo[=bar]
-d foo[=bar]   Define INI entry foo with value bar

to set the correct ini flag.

I wonder if we can just check and auto include a php.ini file in some well known location.