These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.62 s (backtrack: 0/20).

[ebuild  N     ] media-libs/giflib-6.1.3:0/7::gentoo  USE="-doc -static-libs" 460 KiB
[ebuild  NS    ] app-text/docbook-xml-dtd-4.3-r2:4.3::gentoo [4.1.2-r7:4.1.2::gentoo, 4.2-r3:4.2::gentoo, 4.4-r3:4.4::gentoo, 4.5-r2:4.5::gentoo] 82 KiB
[ebuild  N     ] media-libs/libwebp-1.6.0:0/7::gentoo  USE="gif jpeg opengl png tiff -static-libs -swap-16bit-csp" CPU_FLAGS_X86="avx2 sse2 sse4_1" 4196 KiB
[ebuild  N     ] x11-libs/gdk-pixbuf-2.44.8:2::gentoo  USE="gif jpeg tiff -gtk-doc -introspection -test" 5897 KiB
[ebuild  N     ] gui-libs/gdk-pixbuf-loader-webp-0.2.7::gentoo  8924 KiB

Total: 5 packages (4 new, 1 in new slot), Size of downloads: 19557 KiB