Created attachment 523976 [details] build.log The build of app-accessibility/at-spi2-core-2.26.2::gnome[abi_x86_32] aborts with the multilib error message "Header files have changed between ABIs".
Created attachment 523978 [details] emerge --info app-accessibility/at-spi2-core
The fix from bug #650532 comment #2 can also be applied to the at-spi2-* ebuilds to fix this issue.
Created attachment 528218 [details, diff] Patch to fix the at-spi2-core mismatched headers caused by glib-mkenums This patch changes @filename@ to @basename@. This *might* be problematic in the #include in atspi-enum-types.c file (since it's not longer a direct path), but it doesn't seem as though that file is ever installed, meaning it's just the comments that end up installed on the system (and they don't need the full path).
Still using autotools with 2.26.2 in main tree, which uses pregenerated enum types, so no issue. We'll need to make sure it's fixed for meson builds going forward of course, but retargeting the bug to at-spi2-cpre-2.28 (gnome 3.28 material)
Should be fixed in main tree 2.30.* versions that use meson.