Configuring portage

Overlay

layman -a lcd-filtering

Keywords

echo "media-libs/fontconfig ~x86" >> /etc/portage/package.keywords/fonts
echo "media-libs/freetype ~x86" >> /etc/portage/package.keywords/fonts  
echo "x11-libs/cairo ~x86" >> /etc/portage/package.keywords/fonts  
echo "x11-libs/libXft ~x86" >> /etc/portage/package.keywords/fonts

USE flags

echo "media-libs/fontconfig -cleartype lcdfilter" >> /etc/portage/package.use/fonts
echo "media-libs/freetype -bindist -cleartype lcdfilter" >> /etc/portage/package.use/fonts  
echo "x11-libs/cairo -cleartype lcdfilter" >> /etc/portage/package.use/fonts  
echo "x11-libs/libXft -cleartype lcdfilter" >> /etc/portage/package.use/fonts

Installing the packages

emerge -uNav fontconfig freetype cairo libXft