app-emulation/qemu: ebuild maintenance (2.8.0-r5)

app-emulation/qemu: ebuild maintenance (2.8.0-r5)

This commit addresses several bugs in the current dependency handling.

 - Almost all dependencies that were exclusively listed in
   SOFTMMU_LIBS_DEPEND are needed for qemu user targets as well. This is
   evidenced by trying to compile qemu with
     USE="* -static -static-softmmu -static-user"
     QEMU_USER_TARGETS="*" QEMU_SOFTMMU_TARGETS=""
   in a minimal stage-3 environment.

   The only remaining dependencies (exclusive for softmmu system
   targets) are

- always build qemu-tools

- restructure dependencies, bug #611084

Package-Manager: Portage-2.3.3, Repoman-2.3.1