gnus-replace-in-string
gnus-replace-in-string is a compiled Lisp function in `gnus-util.el
'.
(gnus-replace-in-string STRING REGEXP NEWTEXT &optional LITERAL)
Replace all matches for REGEXP with NEWTEXT in STRING.
If LITERAL is non-nil, insert NEWTEXT literally. Return a new
string containing the replacements.
This is a compatibility function for different Emacsen.