Update CMakeLists.txt

Author: anutosh491

test/CMakeLists.txt

@@ -60,6 +60,7 @@ if(EMSCRIPTEN)
     target_link_options(test_xeus_cpp
         PUBLIC "SHELL: -fexceptions"
         PUBLIC "SHELL: -s MAIN_MODULE=1"
+        PUBLIC "SHELL: -s WASM_BIGINT"
         PUBLIC "SHELL: -s ASSERTIONS=0"
         PUBLIC "SHELL: -s ALLOW_MEMORY_GROWTH=1"
         PUBLIC "SHELL: -s EXIT_RUNTIME=1"
@@ -100,4 +101,4 @@ else()
     target_include_directories(test_xeus_cpp PRIVATE ${XEUS_CPP_INCLUDE_DIR})
 
     add_custom_target(xtest COMMAND test_xeus_cpp DEPENDS test_xeus_cpp)
-endif()
+endif()