I just update fontconfig from 2.2.3 to 2.3.2. I am supprised that all my QT
based programs display bold font charactors for Chinese. But actually they
should just display regular font as before. In fact, only SimSun font in my
system is broken. The other fonts seem fine. And the GTK programs also work well.

So I try to find out what is wrong with my system. Finally, I find that fc-cache
must do something wrong with my Chinese fonts. 

I have a SimSun font family and there are four font files for different styles.
Nomally, when I select SimSun, SimSun.ttf should be chosen. But now, when I
select SimSun in QT program, SimSun-Bold.ttf is chosen. 

I do not know what happens. I use the fc-cache from version 2.2.3 to regenerate
the fonts.cache-1 file. Then everything goes ok again. Therefore, I guess the
problem is that fc-cache generates some bad cache file.

I attach the fonts.cache-1 (2.3.2) and fonts.cache-1.bak (2.2.3) as well as two
screenshots which show what happens.