systemd is required too

In the Readme we have this requirements:

Requires Linux 5.2 or newer and GLib.

But trying to compile in slackware i got this:

 meson  ../
The Meson build system
Version: 0.57.1
Source dir: /tmp/low-memory-monitor
Build dir: /tmp/low-memory-monitor/build
Build type: native build
Project name: low-memory-monitor
Project version: 2.1
C compiler for the host machine: ccache cc (gcc 10.2.0 "cc (GCC) 10.2.0")
C linker for the host machine: cc ld.bfd 2.36.1-slack15
Host machine cpu family: x86_64
Host machine cpu: x86_64
Compiler for C supports arguments -fgnu89-inline: YES 
Compiler for C supports arguments -fvisibility=hidden: YES 
Compiler for C supports arguments -std=gnu99: YES 
Compiler for C supports arguments -Wall: YES 
Compiler for C supports arguments -Wundef: YES 
Compiler for C supports arguments -Wunused: YES 
Compiler for C supports arguments -Wstrict-prototypes: YES 
Compiler for C supports arguments -Werror-implicit-function-declaration: YES 
Compiler for C supports arguments -Wno-pointer-sign: YES 
Compiler for C supports arguments -Wshadow: YES 
Compiler for C supports arguments -Wtautological-type-limit-compare: NO 
Found pkg-config: /usr/bin/pkg-config (0.29.2)
Found CMake: /usr/bin/cmake (3.20.0)
Run-time dependency systemd found: NO (tried pkgconfig and cmake)

../meson.build:31:4: ERROR: Dependency "systemd" not found, tried pkgconfig and cmake

A full log can be found at /tmp/low-memory-monitor/build/meson-logs/meson-log.txt

Slackware do not use systemd, but this tool also do not list it as a requirement