For a symbol to start with $, it needs to be escaped with a second
dollar sign: $$. This was not handled correctly, instead $$ was seen
as TOKEN_BASE.
Fix this.
Reported-by: E. C. Masloch <pushbx@ulukai.org>
Fixes: https://bugzilla.nasm.us/show_bug.cgi?id=3392922
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>