Kalendar app won't run?

[victorcleaner]

After installing the all the QT5 & SqLite dev tools + dependencies (mesa, etc...), both qmake & make ran without errors. The Kalendar binary file in the /src folder shows up as "unknown" file type, and is set as executable, too.
OS is Linux Mint 20 Cinn x64, and for some reason the Kalendar file will not run or open... ???
Not sure what is happening, but Timeshift Restored twice reinstall dev tools again, and qmake/make, but still will not run or open. No ~/kalendar folder was created; however, I wasn't sure if that happened after running the app?
Please help,
V

[kalimba666]

Same here:
qmake -> "Info: creating stash file /home/username/Downloads/kalendar-master/src/.qmake.stash
Project ERROR: Unknown module(s) in QT: core gui widgets"

And because of that, I cannot run make. any solution here? I put the zip file in Downloads and extracted it there, too.

[victorcleaner]

What I was saying, is that 'Qmake' did work without errors, and so did 'Make', within the /kalendar-master/src folder.
However, there is a Kalendar(Shared Library), Kalendar.pro(Qt QMake Profile), and Kalendar.pro.user.3148a8b(Markup) file then created within that /kalendar-master/src folder, along with many other files. Only the Kalendar.pro.user.3148a8b file is recognied as an executable file, and it does not 'run' with the Autorun Prompt. (Verified that Executable was checked within permissions.) Double-clicked, the prompt window opens with the options 'run in terminal' / 'display' / 'cancel' / 'run', and 'run' does nothing.
I wish the creator would please respond... what am I missing, within Linux Mint 20.1 Cinnamon 64-bit? Everything else worked to Qmake & Make, but the exec file won't 'run' to open the program.

[cybergrunge-ops]

same issue for me on debian-buster