AWStats

The line:
while ($value =~ /__(\w+)__/) {
makes it impossible to use:
LogFile="/var/log/httpd/__SERVER_NAME___access.log"
which is a requirement of my environment, where other
scripts are based on www.domain.com_access.log and
_error.log files. The pattern match returns
"/var/log/httpd/access.log" as "SERVER_NAME_" is not
defined.

I have replaced the line with:
while ($value =~ /__(\w+[^_])__/) {
which looks for only __SERVER_NAME__, freeing any
remaining underscores to be taken literally.
(Actually, If I did something more like [^_]*, you
would be able to use __VAR1____VAR2__, which I doubt
would work with the current expression.)

Support for litterals "__SERVER_NAME__\_access.log"
would be nice, but that could be a pain for C:\\WINDOWS
users..

This patch will hinder ones ability to use a variable
named VARIABLE_, but I doubt that anyone has this need.