build/link error "undefined reference to `zxdg_*"

[joj-pacovi]

Hi,

I am getting a error when trying to compile wlc-Upstream.
Was not satisfied with the gentoo ebuilds and had the Problem that menus only appeared once in sway which was said to be fixed by compiling wlc from git.

Here is what i issue as commands:
git clone https://github.com/Cloudef/wlc.git
cd wlc/
git submodule update --init --recursive
mkdir target && cd target
cmake -DSOURCE_WLPROTO=ON -DCMAKE_BUILD_TYPE=Upstream ..
make

Here is the Error i get:
Scanning dependencies of target example
[ 94%] Building C object example/CMakeFiles/example.dir/example.c.o
[ 96%] Linking C executable example
../src/libwlc.so.0.0.8: undefined reference to `zxdg_shell_v6_interface'

../src/libwlc.so.0.0.8: undefined reference to `zxdg_positioner_v6_interface'

../src/libwlc.so.0.0.8: undefined reference to `zxdg_surface_v6_interface'

../src/libwlc.so.0.0.8: undefined reference to `zxdg_toplevel_v6_interface'

../src/libwlc.so.0.0.8: undefined reference to `zxdg_popup_v6_interface'

collect2: error: ld returned 1 exit status
make[2]: *** [example/CMakeFiles/example.dir/build.make:98: example/example] Error 1
make[1]: *** [CMakeFiles/Makefile2:1229: example/CMakeFiles/example.dir/all] Error 2
make: *** [Makefile:161: all] Error 2

did i miss something?