[cairo] Does the cairo-1.1.6 pdf backend require gtk+?

[Jeff Kowalczyk]

Does the cairo-1.1.6 pdf backend require gtk+?

I wanted to enable the pdf backend on a (Gentoo Linux) test server
(e.g. no X windows libraries installed), but this dependency clause in the
current Gentoo cairo packaging:

  x11-libs/cairo-1.1.6-r1.ebuild:
  (...)
  pdf? (  >=app-text/poppler-bindings-0.4.1
          x11-libs/pango
          >=x11-libs/gtk+-2 )

Leads to the following dependency chain to satisfy the gtk+ dependency.

  [ebuild  N    ] media-libs/tiff-3.8.2  USE="jpeg zlib -nocxx" 1,304 kB
  [ebuild  N    ] x11-misc/util-macros-1.0.2  USE="-debug" 37 kB
  [ebuild  N    ] x11-proto/kbproto-1.0.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-proto/xextproto-7.0.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-proto/xproto-7.0.5  USE="-debug" 0 kB
  [ebuild  N    ] x11-proto/xf86bigfontproto-1.1.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-proto/inputproto-1.3.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libXau-1.0.1  USE="-debug" 0 kB
  [ebuild  N    ] x11-proto/bigreqsproto-1.0.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libXdmcp-1.0.1  USE="-debug" 0 kB
  [ebuild  N    ] x11-proto/xcmiscproto-1.1.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/xtrans-1.0.0  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libX11-1.0.1  USE="-debug -ipv6" 0 kB
  [ebuild  N    ] x11-proto/renderproto-0.9.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libXrender-0.9.1  USE="-debug" 0 kB
  [ebuild  N    ] x11-proto/fixesproto-4.0  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libXfixes-4.0.1  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libXcursor-1.1.7  USE="-debug" 218 kB
  [ebuild  N    ] x11-proto/xineramaproto-1.1.2  USE="-debug" 0 kB
  [ebuild  N    ] dev-libs/atk-1.11.4  USE="-debug -doc" 606 kB
  [ebuild  N    ] dev-util/intltool-0.35.0  126 kB
  [ebuild  N    ] x11-misc/shared-mime-info-0.17-r2  558 kB
  [ebuild  N    ] x11-libs/libXext-1.0.1  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libXft-2.1.9  USE="-debug" 246 kB
  [ebuild  N    ] x11-libs/pango-1.12.2  USE="-debug -doc" 1,184 kB
  [ebuild  N    ] x11-libs/libICE-1.0.1  USE="-debug -ipv6" 0 kB
  [ebuild  N    ] x11-libs/libSM-1.0.1  USE="-debug -ipv6" 0 kB
  [ebuild  N    ] x11-libs/libXt-1.0.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libXi-1.0.1  USE="-debug" 0 kB
  [ebuild  N    ] x11-proto/randrproto-1.1.2  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/libXrandr-1.1.1  USE="-debug" 0 kB
  [ebuild  N    ] x11-libs/gtk+-2.8.18  USE="jpeg tiff -X -debug -doc -xinerama" 11,971 kB
  [ebuild     U ] app-text/poppler-0.5.3 [0.5.1-r1] USE="jpeg" 1,025 kB
  [ebuild  N    ] app-text/poppler-bindings-0.5.3  USE="cairo -gtk -qt -qt4" 0 kB
  [ebuild     U ] x11-libs/cairo-1.1.6-r1 [1.1.6] USE="pdf% png svg% -X -doc -glitz" 0 kB
  
Is gtk+ necessary? Anything other than poppler, poppler-bindings and
pango? Thanks.