if your running debian sid and KDE , after the latest round of updates (8/24/17) you find your KDE install is borked. here is why:
KDE is linked against libfreetype6.so.6 ver. 2.8 in /usr/local/lib
libfreetype6 is installed in/usr/lib/x86_64-linux-gnu/ by default
solution is to cp (or link i used cp) /usr/lib/x86_64-linux-gnu/libfreetype.so.6 to /usr/local/lib/libfreetype.so.6
like so:
mv /lib/x86_64-linux-gnu/libfreetype.so.6 /usr/local/lib/libfreetype.so.6.old (as needed)
cp /usr/lib/x86_64-linux-gnu/libfreetype.so.6 /usr/local/lib/libfreetype.so.6 this fixed my problem .
here is how i found it:
installed the LXDE suite
opened a terminal
tryed to run a KDE based program (such as dolphin) from said terminal
got an error :
/usr/bin/plasmashell: symbol lookup error: /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5: undefined symbol: FT_Get_Font_Format
or very similar to that
2 days of googling and trying various fixed led me to check the libs that plasmashell was linked to via ldd
ldd /usr/bin/plasmashell |grep free
this revealed that is was linked like so:
libfreetype.so.6 => /usr/local/lib/libfreetype.so.6
that lib is an older version (2.7) than what plasmashell was linked to (2.8)
and that version didnt correctly support FT_Get_Font_Format.