Aaarg! I found this before and didn't make a note. That'll teach me. If you want to set custom environment variables for a particular php site running on apache then you can add them in using
SetEnv where you specify the VirtualHost details. I use the http-vhosts.conf file on my macbook.
Here's an example:
<VirtualHost *:80> ServerAdmin firstname.lastname@example.org DocumentRoot "/path/httpd" ServerName mysite.local ServerAlias mysite.local SetEnv VARNAME myvariable </VirtualHost>
now I shouldn't forget it again