Can't build KDE with kde-builder - stddef.h not fopund

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1

Hi all - I’m lost here. Trying to use kde-builder to build kcoreaddons, but it fails with….

/usr/include/c++/15/cstddef:52:10: fatal error: ‘stddef.h’ file not found

This happens on KUbuntu 25.20. KDE Neon latest version and I have no idea what’s going on.

Any ideas?

Thanks,

Paul

2

… and you have installed ‘build-essential’?

3
4

Hi Storm,

Yes, build-essential is installed.

P

5

Hi,

Thanks for pitching in. I’ve been through all the troubleshooting steps, but it feels like there is something wrong with the compiler systems. Sadly, though, I’m way out of my depth there. What is confusing is that it is the same on various different distros, but with different versions of C++ (13, 14, 15) on Ubuntu and openSuSE.

P

6

Just to double-check, you have been through this step here: Basic troubleshooting | Developer which sounds awfully similar to what you are describing.

I am not familiar with kde-builder as I am not using it. I am compiling manually with cmake. Using this process, I have to make sure that I use the correct version of the package I am building. That is, match the package’s git branch to my locally installed environment.

In case of kcoreaddons, I just tried exactly that: Just grabbing the sources from GitLab and trying to compile won’t work, because upstream main isn’t in line with the frameworks version 6.19 which I have installed. The build will fail. Switching to the correct tag (e.g. git switch –detach v6.19.0) lets me build the package without any problems (given I have all the dependencies installed as in the link from @Herzenschein ).

Does the build work for you if you build manually? A good guide for that is here: Building KDE software manually | Developer

7

So you installed clang (maybe also clang-dev) or disabled building the bindings as mentioned in the link?

8

Hi all…with the pointers you supplied, and a bit of poking around, I got it working.

It seems that the toolchain had different versions of clang (13) and the LLVM (15) stuff - as installed out of the box by the automatic installation system.

I updated to clang 20 and LLVM 20, and it worked with the –refresh-build switch! My guess is that those tools all need to be at the same version, even if it’s not 20.

Thanks for all the support - KDE people are the best!

Paul