CI Tracking issue: LLVM 18 & GCC14 with CUDA error with unsupported __float128

[ahueck]

On Ubuntu 24 runner, the combinaation of Clang/LLVM18 and the gcc-14 installation, we error out due to __float128 is not supported on this target:

In file included from <built-in>:1: 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/lib/llvm-18/lib/clang/18/include/__clang_cuda_runtime_wrapper.h:41: 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/lib/llvm-18/lib/clang/18/include/cuda_wrappers/cmath:27: 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14/cmath:3898: 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14/bits/specfun.h:44: 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14/limits:2089:27: error: __float128 is not supported on this target

Failed solutions

Compiler flags -std=c++17 and __STRICT_ANSI__ do not work in this case.

References

See llvm-project issue 97866 and llvm-project issue 83918