The svg USE-flag is not enabled on PySide by default, and the ebuild for FreeCAD does not require it to be. SVG support in PySide is necessary for the draft mode of FreeCAD to work, and should be required in the FreeCAD ebuild.
commit d06b7207c4aac1a061284f3569fb129b8660bb3d Author: bdouxx <bdouxx-git@yahoo.fr> Date: Wed Dec 28 22:03:03 2016 +0100 media-gfx/freecad: Version bump to 0.16 Gentoo-bug: 580256, 580642, 591012 * change SRC_URI to github