Subject: bug#16731: 24.3.50; , Latin small letter sharp s is not considered lower-case

From: Paul Eggert <[email-masked]>
Date: Fri, 14 Feb 2014 08:20:48 -0800

Grep doesn't just use glibc's tables; it has its own dfa matcher (also 
shared by awk), and runs into problem in this area as well.  I'm working 
on fixes for this in my limited spare time.

If you want 'uppercasep' to match what glibc and grep mean by 
[[:upper:]], Emacs might need to check not merely for 
UNICODE_CATEGORY_Lu but also for other Unicode categories (mixed case, 
title case).  I haven't investigated the details.