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

Calculating dependencies ...

!!! Problem resolving dependencies for =x11-wm/e16-1.0.31
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=x11-wm/e16-1.0.31" has unmet requirements.
- x11-wm/e16-1.0.31::gentoo USE="alsa dbus dialogs nls opengl pango readline sndfile themes xft xrandr xrender xsm xsync -audiofile -debug -doc -editline -examples -gnome -libhack -modules -no-container -player -pulseaudio -sound -xcomposite -xi2 -xinerama -xpresent -zoom"

  The following REQUIRED_USE flag constraints are unsatisfied:
    opengl? ( xcomposite )

  The above constraints are a subset of the following complete expression:
    at-most-one-of ( editline readline ) opengl? ( xcomposite xrender ) pango? ( xft ) sound? ( exactly-one-of ( alsa player pulseaudio ) alsa? ( exactly-one-of ( sndfile audiofile ) ) pulseaudio? ( exactly-one-of ( sndfile audiofile ) ) )