Compiling documentation requires libsystemd, but it is actually optional

[rodolfojcj]

rtpengine version the issue has been seen with

master branch

Used distribution and its version

Rocky 10

Linux kernel version used

6.12.0-124.21.1.el10_1.x86_64

CPU architecture issue was seen on (see uname -m)

x86_64

Expected behaviour you didn't see

At https://rtpengine.readthedocs.io/en/latest/compiling_and_installing.html#manual-compilation we have:

The following software packages including their development headers are required to compile the daemon:
...
libsystemd
...

But in the source code such library is conditionally used, for example in file lib/auxlib.c:

#ifdef HAVE_LIBSYSTEMD
#include <systemd/sd-daemon.h>
#endif

Given that, the documentation can be updated to say something like this:

The following software packages including their development headers are required to compile the daemon:
...
libsystemd (optional for systemd notify support)
...

Note: if libsystemd is not used by rtpengine, then its systemd rtpengine-daemon.service unit file should use Type=simple instead of Type=notify.

Related changes come from commit 5ba5295.

Unexpected behaviour you saw

No response

Steps to reproduce the problem

No response

Additional program output to the terminal or logs illustrating the issue

Anything else?

No response