Duplicates the headers variables while coping data from/to ModSecurity.
This seems to fix the segfault that was happening while using proxy_pass.
The variable is later cleaned, which means that we don't have a leak
because of that.
The nginx config file was looking for depedencies by its own,
by doing that it was ignoring the options that were passed to
configure script. This commit deletes this config file and adds
a meta-config which is populated by configure whenever the
standalone-module is enabled.
The ModSecurity module has some dependencies that may not be part
of the Nginx build, and so it is not part of the configuration
options. In order to resolve this dependencies automatically this
`config' is now making use of the pkg-config, utility that is
popular to make this compatible layer between different Linux
distributions and operational systems.
