When building the plugin from SVN on ArchLinux, I get the following error while running autogen.sh:
configure:3852: error: possibly undefined macro: m4_ifval
If this token and others are legitimate, please use m4_pattern_allow.
See the Autoconf documentation.
I noticed it seems to be related to some autotools and/or libtool stuff. With the attached patch it compiles fine.
Though I'm not yet sure why it does build on other systems without this.
(the above also affects xfce4-taskmanager, xfce4-battery-plugin and xfce4-systemmonitor-plugin, I'll open bugs for these later)
Created attachment 1751
Committed against all the components that you noted down (r5430).
xfce4-eyes-plugin and xfce4-xkb-plugin have the same problem and the same fix works for them
Also done, r5431. Thanks ;)