Add c++20 kernel

CMakeLists.txt

@@ -154,6 +154,7 @@ configure_kernel("share/jupyter/kernels/xcpp")
 configure_kernel("share/jupyter/kernels/xcpp11")
 configure_kernel("share/jupyter/kernels/xcpp14")
 configure_kernel("share/jupyter/kernels/xcpp17")
+configure_kernel("share/jupyter/kernels/xcpp20")
 
 # Source files
 # ============

share/jupyter/kernels/xcpp/kernel.json.in

@@ -1,5 +1,5 @@
 {
-  "display_name": "cpp 17 (xcpp)",
+  "display_name": "cpp 20 (xcpp)",
   "env": {
       "PATH":"@XEUS_CPP_PATH@",
       "LD_LIBRARY_PATH":"@XEUS_CPP_LD_LIBRARY_PATH@"
@@ -10,7 +10,7 @@
       "{connection_file}",
       "-resource-dir", "@XEUS_CPP_RESOURCE_DIR@",
       "-I", "@CMAKE_INSTALL_PREFIX@/include",
-      "-std=c++17"@XEUS_CPP_OMP@
+      "-std=c++20"@XEUS_CPP_OMP@
   ],
   "language": "cpp",
   "metadata": {"debugger": false

share/jupyter/kernels/xcpp20/kernel.json.in

@@ -0,0 +1,18 @@
+{
+  "display_name": "C++20 (xcpp)",
+  "env": {
+      "PATH":"@XEUS_CPP_PATH@",
+      "LD_LIBRARY_PATH":"@XEUS_CPP_LD_LIBRARY_PATH@"
+  },
+  "argv": [
+      "@XEUS_CPP_KERNELSPEC_PATH@xcpp",
+      "-f",
+      "{connection_file}",
+      "-resource-dir", "@XEUS_CPP_RESOURCE_DIR@",
+      "-I", "@CMAKE_INSTALL_PREFIX@/include",
+      "-std=c++20"@XEUS_CPP_OMP@
+  ],
+  "language": "cpp",
+  "metadata": {"debugger": false
+  }
+}