Gentoo's Bugzilla –
Attachment 524366 Details for
Bug 650858media-sound/pulseaudio-11.1 - In file included from .../work/pulseaudio-11.1/src/pulsecore/shm.c:48:0: .../work/pulseaudio-11.1/src/pulsecore/memfd-wrappers.h:36:19: error: static declaration of ‘memfd_create’ follows non-static declaration