[BRLTTY] brltty.service fails to start on archlinux

[Bernhard Landauer]

Dear brltty developers,

we are trying to use brltty on the sonar mate and Gnome edition (based 
on Manjaro/Archlinux) but starting the service gives these errors:

cannot load speech driver: /usr/lib/brltty/libbrlttysauto.so
speech driver not loadable: auto
/usr/lib/brltty/libbrlttysspeech-dispatcher.so: cannot open shared 
object file: No such file or directory
cannot load speech driver: /usr/lib/brltty/libbrlttysspeech-dispatcher.so
speech driver not loadable: speech-dispatcher

The source used for our latest package 5.3.1 is
http://mielke.cc/brltty/archive/brltty-5.3.1.tar.xz

Our service file:

################################

[Unit]
Description=Braille Console Driver
DefaultDependencies=no
Before=sysinit.target

[Service]
ExecStart=/usr/bin/brltty --pid-file=/run/brltty.pid
Type=forking
PIDFile=/run/brltty.pid

[Install]
WantedBy=sysinit.target

################################

Thank you for you help!
regards
Bernhard Landauer