can't build without systemd

Hi,

thanks your your works! As i saw, systemd is still optional, but i can't build knot-resolver without systemd. On my system i use eudev and openrc, also use "-Dsystemd_files=disabled", but meson ended with error:

alois@picasso knot-resolver]$ meson build_arch \
         --buildtype=release \
         --prefix=/usr \
         --sbindir=bin \
         -Dkeyfile_default=/etc/trusted-key.key \
         -Dsystemd_files=disabled \
         -Dclient=enabled \
         -Dinstall_kresd_conf=enabled \
         -Dunit_tests=enabled

The Meson build system
Version: 0.54.3
Source dir: /tmp/makepkg/knot-resolver/src/knot-resolver
Build dir: /tmp/makepkg/knot-resolver/src/knot-resolver/build_arch
Build type: native build
Project name: knot-resolver
Project version: 5.1.2
C compiler for the host machine: cc (gcc 10.1.0 "cc (GCC) 10.1.0")
C linker for the host machine: cc ld.bfd 2.34.0
C++ compiler for the host machine: c++ (gcc 10.1.0 "c++ (GCC) 10.1.0")
C++ linker for the host machine: c++ ld.bfd 2.34.0
Host machine cpu family: x86_64
Host machine cpu: x86_64
Message: --- required dependencies ---
Found pkg-config: /bin/pkg-config (1.7.3)
Run-time dependency libknot found: YES 2.9.5
Run-time dependency libdnssec found: YES 2.9.5
Run-time dependency libzscanner found: YES 2.9.5
Run-time dependency libuv found: YES 1.38.1
Run-time dependency lmdb found: YES 0.9.25
Run-time dependency gnutls found: YES 3.6.14
Run-time dependency luajit found: YES 2.0.5
Message: ------------------------------
Message: --- optional dependencies ---
Run-time dependency openssl found: YES 1.1.1g
Checking for function "asprintf" : YES 
Run-time dependency libcap-ng found: YES 0.7.10
Checking for function "sendmmsg" : YES 
Run-time dependency libsystemd found: YES 243.7
Message: ---------------------------

meson.build:168:10: ERROR: String '243.7' cannot be converted to int

Any idea ?