MacOS - difficulty configuring cmake

[SGSSGene]

One of our students has followed the seqan3 setup tutorial, but gets stuck at the cmake configuration step.
The repository was cloned with --recursive-submodules. The file submodules/sdsl-lite/include/sdsl/version.hpp exists.
But for some reason check_include_file_cxx can't find sdsl/version.hpp.
We also printed the content of CMAKE_REQUIRED_INCLUDES (which can be seen on the log below).
But for some reason it still dosn't find it.
I can't reproduce this on other MacOS systems.

cmake is version 3.22.1

Any Ideas what to try next? @eseiler

-- Finding SeqAn3 and checking requirements:
--   SeqAn3 include dir found:  
/System/Volumes/Data/Education/internship/tutorial/seqan3/include
--   Detected as running from a repository checkout…
--     …adding submodule include: 
/System/Volumes/Data/Education/internship/tutorial/seqan3/submodules/cereal/include
--     …adding submodule include: 
/System/Volumes/Data/Education/internship/tutorial/seqan3/submodules/sdsl-lite/include
--     …adding submodule include: 
--   C++ Standard-20 support:    via -std=c++20
--   C++ Concepts support:       via -std=c++20
--   Thread support:             builtin.
;/System/Volumes/Data/Education/internship/tutorial/seqan3/include;/System/Volumes/Data/Education/internship/tutorial/seqan3/submodules/cereal/include;/System/Volumes/Data/Education/internship/tutorial/seqan3/submodules/sdsl-lite/include;/System/Volumes/Data/Education/internship/tutorial/seqan3/submodules/sharg-parser/include
CMake Error at
/System/Volumes/Data/Education/internship/tutorial/seqan3/build_system/seqan3-config.cmake:115
(message):
  The SDSL library is required, but wasn't found.  Get it from
  https://github.com/xxsds/sdsl-lite
Call Stack (most recent call first):
  /System/Volumes/Data/Education/internship/tutorial/seqan3/build_system/seqan3-config.cmake:345
(seqan3_config_error)
  CMakeLists.txt:8 (find_package)

[eseiler]

Maybe compiler include paths are missing? Then the version.hpp would not compile. Could be checked by looking for cereal before sdsl. If so, the compiler isn't configured correctly.

[SGSSGene]

We removed the check for sdsl check, but than it just hangs with the check for Sharg.

[SGSSGene]

This is fixed by setting export CXX=g++-11 before calling cmake the first time. Since it is a mac, it otherwise uses gcc which is just a symlink to clang. But it is still unclear to me, why this exactly causes this behavior. I would have expected these lines to still pass without problems.