which has a link to the full specification on the top.
Best would be if the .desktop file would be installed to /usr/share/applications in the makefile install target, and the icon to /usr/share/icons/{size}/apps (folder depending on the icon size).
I added 48x48 icons (.png) and .desktop files for boulder and mapeditor in /exe/linux_x64. There is still no usage of those files, pending further changes to Makefile or other files.
You should include a desktop file and an icon with the project - for the freedesktop standard, see
https://www.freedesktop.org/wiki/Howto_desktop_files/
which has a link to the full specification on the top.
Best would be if the .desktop file would be installed to /usr/share/applications in the makefile install target, and the icon to /usr/share/icons/{size}/apps (folder depending on the icon size).