Compiler warning about undefined variable UNICODE::OFFSET
## Describe the bug
Compiler warning:
```
; File: /home/toy/src/clnet/cmucl/dev/cmucl/src/code/unicode.lisp
; In: DEFUN UNICODE::STRING-CAPITALIZE-SIMPLE
; (WITH-ONE-STRING STRING START END OFFSET ...)
; Warning: Undefined variable UNICODE::OFFSET
```
Probably introduced when moving this function from `code/string.lisp`
to `code/uincode.lisp`.
Also:
```
; File: /home/toy/src/clnet/cmucl/dev/cmucl/src/code/unicode.lisp
; In: DEFUN UNICODE::CHAR-TITLECASE
; (UNICODE-TITLE M)
; Warning: Undefined function UNICODE::UNICODE-TITLE
;
; In: DEFUN UNICODE::STRING-CAPITALIZE-SIMPLE
; (WITH-ONE-STRING STRING START END OFFSET ...)
; Warning: Undefined function UNICODE::WITH-ONE-STRING
; ;
; Warning: These variables are undefined:
; UNICODE::+ASCII-LIMIT+ SYSTEM::ERR UNICODE::OFFSET
```
## To Reproduce
Steps to reproduce the behavior:
1. Build cmucl
2. Look at `<build>/compile-lisp.log`
## Expected behavior
There shouldn't be an undefined variable here.
## Desktop (please complete the following information):
- OS: All
issue