Revert 42b81966b7 due to GitHub failures

PiperOrigin-RevId: 862869742
Change-Id: I9c56c8e15b609c9a67e6c90542722e7326d8fe2c

wasm/CMakeLists.txt

@@ -14,6 +14,8 @@
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/wasm/dist")
 
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -O3 -fexceptions")
+
 set(CMAKE_INSTALL_PREFIX ${PROJECT_SOURCE_DIR}/wasm)
 
 include_directories(${PROJECT_SOURCE_DIR}/include)
@@ -31,11 +33,12 @@ if(NOT MUJOCO_WASM_FILES)
     message(FATAL_ERROR "No source files found in codegen/generated/")
 endif()
 
+add_compile_options(-pthread)
+add_compile_options(-fexceptions)
+
 # Set Emscripten linker flags
 set(EMCC_LINKER_FLAGS
     "--bind"
-    "-pthread"
-    "-s PTHREAD_POOL_SIZE=navigator.hardwareConcurrency"
     "-s ASSERTIONS=1"
     "-s ALLOW_MEMORY_GROWTH=1"
     "-s EXPORT_ES6=1"