After a successful build you can run Wireshark right from the build directory. Still the program would need to know that it's being run from the build directory and not from its install location. This has inpact on the directories where the program can find the other parts and relevant data files.

In order to run the Wireshark from the build directory set the environment variable WIRESHARK_RUN_FROM_BUILD_DIRECTORY and run Wireshark. If your platform is properly setup, your build directory and current working directory are not in your PATH, so the commandline to launch Wireshark would be: WIRESHARK_RUN_FROM_BUILD_DIRECTORY=1 ./wireshark.

There's no need to run Wireshark as root user, you just won't be able to capture. When you opt to run Wireshark this way, your terminal output can be informative when things don't work as expected.

During the build all relevant program files are collected in a subdirectory wireshark-gtk2. You can run the program from there by launching the wireshark.exe executable.