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

Calculating dependencies  ..... done!
[ebuild   R   ] dev-util/subversion-1.6.2  USE="apache2 bash-completion dso* nls perl python sasl webdav-neon -berkdb -ctypes-python -debug -doc -emacs -extras -gnome-keyring -java -ruby -test -vim-syntax -webdav-serf" 5,343 kB

Total: 1 package (1 reinstall), Size of downloads: 5,343 kB

!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:

dev-util/subversion:0

  ('installed', '/', 'dev-util/subversion-1.6.2', 'nomerge') pulled in by
    dev-util/subversion[-dso] required by ('installed', '/', 'dev-util/git-1.6.3.3', 'nomerge')
    (and 2 more)

  ('ebuild', '/', 'dev-util/subversion-1.6.2', 'merge') pulled in by
    >=dev-util/subversion-1.5.4[webdav-neon] required by ('installed', '/', 'app-portage/layman-1.2.3', 'nomerge')
    dev-util/subversion required by world

  Explanation:

    New USE for 'dev-util/subversion:0' are incorrectly set. In order to
    solve this, adjust USE to satisfy 'dev-util/subversion[-dso]'.