`emerge -a1 x11-proto/xcb-proto` solves issue, otherwise, fails in configure mentioning lack of xcb-proto files. I'm unsure if the priority is right, but this keeps people from using xorg-server on the architecture which is a fairly important package.
I don't find any dependency in libxcb itself. Possibly a case similar to bug 379545. Please attach config.log
Created attachment 464740 [details] x11-libs/libxcb-1.12-r2 config.log
I can add that the bug you referenced looks very similar to issues I was experiencing with this and other packages. I have a list of packages I may need to file reports for based on the resolution to this ticket.
the config.log, bug description and bug title don't match. Probably should have guessed it, as there is no xorg-proto package in tree. According to config.log you are missing xcb-proto, however: --- $ equery g libxcb-1.12-r2 * Searching for libxcb1.12-r2 ... * dependency graph for x11-libs/libxcb-1.12-r2 `-- x11-proto/xcb-proto-1.12-r2 (>=x11-proto/xcb-proto-1.12-r1) amd64 [abi_x86_32(-)? abi_x86_64(-)? abi_x86_x32(-)? abi_mips_n32(-)? abi_mips_n64(-)? abi_mips_o32(-)? abi_ppc_32(-)? abi_ppc_64(-)? abi_s390_32(-)? abi_s390_64(-)? python_targets_python3_5(-) python_single_target_python3_5(+)] So either this is an eclass problem which is arm64 specific, or something else is wrong.
Ah wait, you are cross compiling. Nevermind. *** This bug has been marked as a duplicate of bug 558774 ***
Whoops, sorry about the title. It is probably arm64 specific which is why I marked it with the architecture. The exact same package merges will work on the x86_64 host. As to why it is arm64 specific I have no idea; that dependencies could be lost (and for more than just this package, and for more than just packages related to X11) is very bizarre.
Wait, why is cross compiling a valid reason to mark this bug as RESOLVED?
The bug is not arm64-specific, it is cross-compiling specific. Please continue discussion in the other bug which this one has been marked as a duplicate of.
