Use more externals from GNU R for the stats package

...uffle.r.native/gnur/patch/src/library/stats/src/Srunmed.c

...uffle.r.native/gnur/patch/src/library/stats/src/Trunmed.c

...r.native/gnur/patch/src/library/stats/src/gnur_extracts.c

...e.truffle.r.native/gnur/patch/src/library/stats/src/nls.c

....truffle.r.native/gnur/patch/src/library/stats/src/port.c

....r.native/gnur/patch/src/library/stats/src/statsR_dummy.c

...le.truffle.r.native/gnur/patch/src/library/stats/src/ts.c

.../nodes/builtin/base/foreign/CallAndExternalFunctions.java

documentation/dev/build-process.md

mx.fastr/copyrights/overrides