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

Calculating dependencies ... done!
Dependency resolution took 1.00 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/tinyxml-2.6.2-r5::gentoo  USE="stl -debug -doc -static-libs" 206 KiB
[ebuild  N     ] dev-libs/libusb-1.0.30:1::gentoo  USE="-debug -doc -examples -static-libs -test -udev -verify-sig" 641 KiB
[ebuild  N     ] virtual/libusb-1-r2:1::gentoo  USE="-udev" 0 KiB
[ebuild  N     ] dev-libs/OpenNI-1.5.7.10-r4::gentoo  USE="opengl -doc -java" 22831 KiB

Total: 4 packages (4 new), Size of downloads: 23677 KiB