Gentoo's Bugzilla –
Attachment 845940 Details for
Bug 889004x11-libs/gtk+-3.24.35 fails to compile (lto): /usr/include/sysprof-4/sysprof-capture-writer.h:169:23: error: type of 'sysprof_capture_writer_set_counters' does not match original declaration [-Werror=lto-type-mismatch]