Enable DIA file support via app-office/dia

Packages describing “dia” as local USE flag

Package “dia” Flag Description
media-gfx/fim Enable DIA file support via app-office/dia
media-gfx/inkscape Enable DIA flow chart import via app-office/dia
app-office/lyx Add support for diagrams (app-office/dia)

All packages providing a “dia” USE flag (3)