Checkout and Build
ncvs co -r SpiderMonkey140_NES40Rtm_Branch mozilla/js/src
nget NSPR
ncd mozilla/js/src
ngmake -f Makefile.ref JS_THREADSAFE=1 JS_LIVECONNECT=1 NES40=1 (other flags also)
nlibjs.so libjsj.so (or js32.dll)