This problem got lost in the other thread. Namely that regex does not accept option flags 128, 256 or 1024.
> (regex "x" "xxx" 128)
ERR: regular expression in function regex : "offset 0 unknown option bit(s) set"
> (regex "x" "xxx" 256)
ERR: regular expression in function regex : "offset 0 unknown option bit(s) set"
> (regex "x" "xxx" 1024)
ERR: regular expression in function regex : "offset 0 unknown option bit(s) set"
The options PCRE_NOTBOL 128, PCRE_NOTEOL 256 and PCRE_NOTEMPTY 1024 now work:
http://www.newlisp.org/downloads/development/inprogress/
Ps: updated again: 2015-08-09 16:32
Ps: see also post in newS section of forum about the significance of the PCRE_UTF8 option (--> Ted Walther)