Please fast-track stabilize dev-libs/gobject-introspection-1.30.0-r2. Earlier versions (e.g. the recently stabilized dev-libs/gobject-introspection-1.30.0-r1) fail to generate cairo introspection files if cairo is not found, which breaks gtk+ and librsvg on new installs of gentoo since gobject-introspection is typically scheduled to emerge before cairo; see bug #391213. Note that if cairo is already installed, the gobject-introspection-1.30.0-r2 ebuild behaves identically to 1.30.0-r1, so this is a low-risk update.
Created attachment 299413 [details] gobject-introspection.report Arch tested on x86, all good here ...
amd64 stable
x86 stable
arm stable
Stable for HPPA and closing.