Gentoo's Bugzilla –
Attachment 602694 Details for
Bug 704896x11-libs/cairo-1.16.0-r3 - In file included from .../work/cairo-1.16.0/src/cairo-xlib-display.c:40: .../work/cairo-1.16.0/src/cairo-xlib-xrender-private.h:106:16: error: redefinition of 'struct _XLinearGradient'