Add compile-time check for #1720 (#1722)

Author: franzpoeschel

include/openPMD/openPMD.hpp

@@ -25,6 +25,21 @@
 namespace openPMD
 {}
 
+#if defined(CUDA_VERSION) && !defined(OPENPMD_SKIP_CHECK_ISSUE_1720)
+static_assert(__cplusplus < 202002L || CUDA_VERSION >= 12040, R"(
+Cannot use the openPMD-api in C++20 projects under a Cuda version lower
+than 12.4.0 due to a bug in the implementation of std::variant.
+Further information at:
+https://github.com/openPMD/openPMD-api/issues/1720
+https://forums.developer.nvidia.com/t/nvcc-c-20-std-variant-complie-failed/270162/5
+This cannot be fixed on our side, please either upgrade to CUDA >= 12.4.0
+or use C++17.
+If you think that this assertion is shown wrongly, please apply
+'#define OPENPMD_SKIP_CHECK_ISSUE_1720' before including
+'<openPMD/openPMD.hpp>'.
+)");
+#endif
+
 // IWYU pragma: begin_exports
 #include "openPMD/Dataset.hpp"
 #include "openPMD/Datatype.hpp"