str-s-from:dstrings — ordinary primitive
Drop a$ from the string stack and leave it as a Forth string a.str, without copying. <ansref>"string-s-from"</ansref>
WARNING: If a$ is a bound string, it may move or disappear at the next garbage collection, making a.str invalid. This can be avoided by sandwiching sections of code where this could occur between $GC-OFF and $GC-ON.