[tde-devels] Compiler version to build kontact

Hello, which compiler version is used to build kontact-trinity and where can I find this information? I'm asking because my task is to build a different "fork" of kontact 3.5 on Bullseye and that build doesn't work yet so I want to compare that fork with the TDE version of kontact so I can patch the fork. I have to admit that I know little about building packages. Still, it's my task so somehow I have to find my way through. Greetings, Christoph