This directory stores modules which require external libraries to compile.
For example, m_filter_pcre requires the PCRE libraries.

To compile any of these modules first ensure you have the required dependencies
(read the online documentation at http://www.inspircd.org/wiki/) and then cp
the .cpp file from this directory into the parent directory (src/modules/) and
re-configure your inspircd with ./configure -modupdate to detect the new module.

NOTE: Some modules require you to copy other dependencies too, such as a related header.
If you get missing header errors when building these modules, check that the header is
not within modules/extra before checking for external dependencies.