known-issues: cuda 11.x with modern glibc and CMake

Keeping track of the know incompatibility in the toolchain.

Signed-off-by: Luc Berger-Vergiat <lberge@sandia.gov>

docs/source/known-issues.rst

@@ -28,6 +28,8 @@ CUDA
 
   Therefore, from version 4.5, the default behavior for Kokkos is to preventively disable `cudaMallocAsync.`
 
+- cuda 11.0 and 11.2 are not compatible with glibc 2.34 librt stubs. That issue is related to how the CMake package handles linking with librt. For more information please look at issue `#7512 <https://github.com/kokkos/kokkos/issues/7512>`_.
+
 
 HIP
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