thanks but this only helps partially. It seems to be the build tools for GNUStep are again broken. This is the thing which drives every newcommer mad and was driving me mad initially too. All the readme's and hints you find on the internet are already obsolete.
Now I get this error: [ 7%] Built target objc-static [ 7%] Linking C shared library libobjc.so clang: error: no such file or directory: 'pthread'; did you mean '-pthread'? make[2]: *** [CMakeFiles/objc.dir/build.make:518: libobjc.so.4.6] Error 1 make[1]: *** [CMakeFiles/Makefile2:476: CMakeFiles/objc.dir/all] Error 2 make: *** [Makefile:163: all] Error 2 This is now under Debian10 with clang-10 from the llvm repo. cmake is very cryptic here to tell us where it breaks. so go figure....