Fix compile errors of workloads due to emsdk version upgrade,
enable BUILD_TARGET auto set for some samples,
and call wasm_runtime_init_thread_env() for in thread routine which
was created by pthread_create but not runtime in spawn-thread sample.
Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>
Implement spec reference-types proposal for interpreter, AOT and JIT, update documents and add sample. And upgrade AOT_CURRENT_VERSION to 3 as AOT file format and AOT module instance layout are changed.
Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>
