There are currently two versions of SVGALIB around, 1.4 and the development Version 1.9, so i suppose to define a SLOT for each version, so that portage won't downgrade 1.9
SVGALIB 1.4.* should get SLOT 1.4
SVGALIB 1.9.* should get SLOT 2.0
Why? Whatever compiles/runs with 1.9 as well, so binary compat seems to stay.
Created attachment 10576 [details, diff]
Weird... I did include that patch on different bug... (?!?)
see azarah's comment