Customizable server and script name

[olegfedoseev]

I added an ability to set server_name and script_name from variables (e.g.: $sent_http_x_pinba_server, header sent from PHP).
Now, before $pinba_request_uri it looks at pinba_script_name, and only if it's empty or failed to parse, it will use variable as fallback.
And, now we can customize server_name as well (why can't we do that earlier?:)) with similar logic - first, it looks at pinba_server_name, and if it failed or empty, then it fallback to default.

P.S. It was like third time when i wrote C, so maybe i implemented it not the way it should be, but it works :)

[olegfedoseev]

Example usage:

fastcgi_hide_header X-Pinba-Server;
fastcgi_hide_header X-Pinba-Script;

pinba_server_name $upstream_http_x_pinba_server;
pinba_script_name $upstream_http_x_pinba_script;