This PR is created to describe my patch to fix #227 and it is by no means a complete patch ready for merge.

The patch contains several unrelated changes, namely:

• Logger change, from dd to ngx_log_error to accomodate my own debugging need
• Removal of ngx_http_modsecurity_pcre_malloc_init and ngx_http_modsecurity_pcre_malloc_done. They are not used in my configuration where PCRE2 is used, and it looks suspicious for SEGVs so I commented them out as a precaution.
• Why use NGX_OK in logging handler? Changed to NGX_DECLINED.

Not yet implemented:

• I'm not sure whether logging phase would take advantage of this. I did not change that yet.
• Missing a NGX_THREADS guard for Nginx setup without threading support.

Currently it passes all test suites and performs well in production.

Benchmarking is welcomed.