[gentoo-user] fcitx crash----something to do with libpng & cairo?

[Jackie]

I am use fcitx for Chinese & after updating few packages today,fcitx just  
crash on startup and won't work even I start it in a terminal.I searched  
through Internet and figured it that this may have some thing to do with  
update libpng and cairo.One way out,however,may be just downgrade libpng &  
cairo,which seem to involve tons of recompilation of related packages(got  
that after mask the update & emerge libpng cairo -pv). So,anyone met this  
& got a better solution?
BTY,using fcitx 4.2.7,libpng-1.6.1:0/16 and cairo-1.12.14. HELP ME OUT:(