Add ddappsec.so to datadog extension

[annuh]

Fixes https://github.com/brefphp/extra-php-extensions/issues/456.

Proposed fix: Include the ddappsec.so module in the Datadog layer.

Without this fix, I'm getting the following errors:

Warning: PHP Startup: Unable to load dynamic library 'ddappsec.so' (tried: /opt/bref/extensions/ddappsec.so (/opt/bref/extensions/ddappsec.so: cannot open shared object file: No such file or directory), /opt/bref/extensions/ddappsec.so.so (/opt/bref/extensions/ddappsec.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0

[annuh]

I don't think we should fix this here, and instead wait for the upstream fix to be completed.

Based on that ticket (https://github.com/DataDog/dd-trace-php/issues/2014), it's not clear to me what exactly will be fixed. Maybe this fix (or: work-around) will still be needed, because the datadog-php-trace setup script assumes ddappsec.so is always present, in a normal installation.

EDIT: this is also described in the documentation:

When you do not specify --enable-appsec, the AppSec extension loads shortly at startup, and is not enabled by default. It immediately short-circuits, causing negligible performance overhead. Source: https://docs.datadoghq.com/tracing/trace_collection/dd_libraries/php/?tab=otherenvironments

[Nyholm]

Hm... I think this is reasonable. Anything happened for DataDog the past few months?

[annuh]

Hm... I think this is reasonable. Anything happened for DataDog the past few months?

Not as far I know. The Datadog docs still mention that “the AppSec extension loads shortly at startup”. Also, the Unable to load dynamic library 'ddappsec.so' warning is still logged. To avoid this warning, it would be nice if this PR could be merged 🙂