Additional side-effect-free functions

[Jonathan Yavner]

Many built-in functions without apparent side effects are not given
the property (side-effects t) in byte-opts.el.  Why not?

Examples:
    make-symbol, char-to-string, format-time-string, current-time,
    truncate, copy-sequence, fround, sxhash, copy-alist, region-end,
    char-equal, plist-member, byte-code-function-p, float-time,
    symbol-name, safe-length, current-time-string, plist-get,
    make-list, fceiling, make-string, bool-vector-p, encode-time,
    prin1-to-string, rassoc, read-from-string, error-message-string,
    decode-time, ftruncate, current-time-zone, wholenump,
    compare-strings, ffloor, intern-soft