What about :
Code:
fastcgi param HTTP on;
http://daemonforums.org/showthread.php?t=8965
Might help you, but it is Nginx and that is also what I use, I don't normaly use httpd, and am not at all a expert.
I think it would help if you could give more information, like show the complete httpd.conf, and also some explanantion about what what you need to accomplish, I did a lot of searching, and did not find anything using a line like what you show,
Code:
fastcgi param HTTP_HOST "test.example.com"
Where did you get that example ? The more details you give, the more someone can help, a description about what your server needs to do, why you need "prefork 10" ? It might seem irrelevant, but with better details, I think I could find some better examples, that fit your situation better. There is a lot of information available, but I do not know enough about your goal,and system to be able to guess at what might best apply.
======edited===
This is one document I found that might help you:
https://www.openbsd.org/papers/httpd-asiabsdcon2015.pdf
====================
http://www.protoc.org/blog/2014/11/2...-httpd-server/