So, after downloading it, I created a build directory inside the source file, enter inside this directory and ran “cmake ..”.

Unfortunatelly I was getting this nasty error:

CMake Error at cmake/thirdpartydeps.cmake:54 (MESSAGE):
  Cannot find plib header files
Call Stack (most recent call first):
  src/libs/tgfclient/CMakeLists.txt:13 (ADD_PLIB_INCLUDEDIR)


-- Configuring incomplete, errors occurred!
See also "/home/alan/Downloads/Cura-5.3.1/CMakeFiles/CMakeOutput.log".
See also "/home/alan/Downloads/Cura-5.3.1/CMakeFiles/CMakeError.log".

Fortunately the solution was here: https://sourceforge.net/p/speed-dreams/discussion/865036/thread/7e2ee9af/

Not exactly, because “cmake -i” is no log supported, but it gave me a hint, and then I did it:

$ cmake -DPLIB_INCLUDE_DIR=/usr/include/plib ..