PeGa!

j-g-, I posted in that way because the output *really* said nothing. For the sanity of the post, Here's the complete output:
# emerge -vat libvirt These are the packages that would be merged, in reverse order: Calculating dependencies... done! [ebuild N ] app-emulation/libvirt-1.2.6:0/1.2.6 USE="caps fuse libvirtd macvtap nls policykit qemu udev vepa -audit -avahi -firewalld -iscsi -lvm -lxc -nfs -numa -openvz -parted -pcap -phyp -rbd -sasl (-selinux) -systemd -uml -virt-network -virtualbox -xen" 28,659 kB [ebuild N ] app-emulation/qemu-2.1.0 USE="aio alsa bluetooth caps curl fdt filecaps gtk jpeg ncurses nls opengl pin-upstream-blobs png python sdl seccomp threads usb usbredir uuid vhost-net vnc xattr -accessibility -debug -glusterfs -infiniband -iscsi -lzo -nfs -numa -pulseaudio -rbd -sasl (-selinux) -smartcard -snappy -spice -ssh -static -static-softmmu -static-user -systemtap -tci {-test} -tls -vde -virtfs -xen -xfs" PYTHON_TARGETS="python2_7" QEMU_SOFTMMU_TARGETS="i386 x86_64 -aarch64 -alpha -arm -cris -lm32 -m68k -microblaze -microblazeel -mips -mips64 -mips64el -mipsel -moxie -or32 -ppc -ppc64 -ppcemb -s390x -sh4 -sh4eb -sparc -sparc64 -unicore32 -xtensa -xtensaeb" QEMU_USER_TARGETS="i386 x86_64 -aarch64 -alpha -arm -armeb -cris -m68k -microblaze -microblazeel -mips -mips64 -mips64el -mipsel -mipsn32 -mipsn32el -or32 -ppc -ppc64 -ppc64abi32 -s390x -sh4 -sh4eb -sparc -sparc32plus -sparc64 -unicore32" 23,012 kB [ebuild NS ] x11-libs/vte-0.36.3:2.90 [0.28.2-r206:0] USE="-debug -glade -introspection" 0 kB [ebuild N ] dev-libs/yajl-2.0.4-r3 USE="-static-libs" 81 kB [ebuild N ] net-analyzer/netcat6-1.0-r2 USE="bluetooth nls -ipv6" 259 kB [ebuild N ] app-text/xhtml1-20020801-r4 227 kB [nomerge ] app-emulation/qemu-2.1.0 USE="aio alsa bluetooth caps curl fdt filecaps gtk jpeg ncurses nls opengl pin-upstream-blobs png python sdl seccomp threads usb usbredir uuid vhost-net vnc xattr -accessibility -debug -glusterfs -infiniband -iscsi -lzo -nfs -numa -pulseaudio -rbd -sasl (-selinux) -smartcard -snappy -spice -ssh -static -static-softmmu -static-user -systemtap -tci {-test} -tls -vde -virtfs -xen -xfs" PYTHON_TARGETS="python2_7" QEMU_SOFTMMU_TARGETS="i386 x86_64 -aarch64 -alpha -arm -cris -lm32 -m68k -microblaze -microblazeel -mips -mips64 -mips64el -mipsel -moxie -or32 -ppc -ppc64 -ppcemb -s390x -sh4 -sh4eb -sparc -sparc64 -unicore32 -xtensa -xtensaeb" QEMU_USER_TARGETS="i386 x86_64 -aarch64 -alpha -arm -armeb -cris -m68k -microblaze -microblazeel -mips -mips64 -mips64el -mipsel -mipsn32 -mipsn32el -or32 -ppc -ppc64 -ppc64abi32 -s390x -sh4 -sh4eb -sparc -sparc32plus -sparc64 -unicore32"  [ebuild N ] sys-firmware/ipxe-1.0.0_p20130925 USE="qemu usb -iso -undi -vmware" 2,188 kB [nomerge ] app-emulation/libvirt-1.2.6:0/1.2.6 USE="caps fuse libvirtd macvtap nls policykit qemu udev vepa -audit -avahi -firewalld -iscsi -lvm -lxc -nfs -numa -openvz -parted -pcap -phyp -rbd -sasl (-selinux) -systemd -uml -virt-network -virtualbox -xen"  [ebuild N ] net-libs/libtirpc-0.2.5 USE="-ipv6 -kerberos -static-libs" 458 kB [nomerge ] app-emulation/qemu-2.1.0 USE="aio alsa bluetooth caps curl fdt filecaps gtk jpeg ncurses nls opengl pin-upstream-blobs png python sdl seccomp threads usb usbredir uuid vhost-net vnc xattr -accessibility -debug -glusterfs -infiniband -iscsi -lzo -nfs -numa -pulseaudio -rbd -sasl (-selinux) -smartcard -snappy -spice -ssh -static -static-softmmu -static-user -systemtap -tci {-test} -tls -vde -virtfs -xen -xfs" PYTHON_TARGETS="python2_7" QEMU_SOFTMMU_TARGETS="i386 x86_64 -aarch64 -alpha -arm -cris -lm32 -m68k -microblaze -microblazeel -mips -mips64 -mips64el -mipsel -moxie -or32 -ppc -ppc64 -ppcemb -s390x -sh4 -sh4eb -sparc -sparc64 -unicore32 -xtensa -xtensaeb" QEMU_USER_TARGETS="i386 x86_64 -aarch64 -alpha -arm -armeb -cris -m68k -microblaze -microblazeel -mips -mips64 -mips64el -mipsel -mipsn32 -mipsn32el -or32 -ppc -ppc64 -ppc64abi32 -s390x -sh4 -sh4eb -sparc -sparc32plus -sparc64 -unicore32"  [ebuild N ] sys-firmware/vgabios-0.7a-r1 USE="-binary -debug" 1,474 kB [ebuild N ] sys-devel/dev86-0.16.21 701 kB [ebuild N ] sys-libs/libseccomp-2.1.1 USE="-static-libs" 111 kB [ebuild N ] sys-firmware/seabios-1.7.5 USE="binary" 603 kB [ebuild N ] sys-apps/usbredir-0.7 USE="-static-libs" 310 kB [ebuild N ] sys-firmware/sgabios-0.1_pre8 30 kB [ebuild N ] sys-apps/dtc-1.4.0 USE="-static-libs" 103 kB [nomerge ] app-emulation/libvirt-1.2.6:0/1.2.6 USE="caps fuse libvirtd macvtap nls policykit qemu udev vepa -audit -avahi -firewalld -iscsi -lvm -lxc -nfs -numa -openvz -parted -pcap -phyp -rbd -sasl (-selinux) -systemd -uml -virt-network -virtualbox -xen"  [ebuild N ] app-misc/scrub-2.5.2 158 kB  [blocks B ] net-analyzer/netcat ("net-analyzer/netcat" is blocking net-analyzer/netcat6-1.0-r2) Total: 16 packages (15 new, 1 in new slot), Size of downloads: 58,367 kB  Conflict: 1 block (1 unsatisfied)Error: The above package list contains packages which cannot beinstalled at the same time on the same system.(net-analyzer/netcat-110-r9::gentoo, installed) pulled in by  net-analyzer/netcat required by @selected (net-analyzer/netcat6-1.0-r2::gentoo, ebuild scheduled for merge) pulled in by  >=net-analyzer/netcat6-1.0-r2 required by (app-emulation/libvirt-1.2.6::gentoo, ebuild scheduled for merge) For more information about Blocked Packages, please refer to the following  section of the Gentoo Linux x86 Handbook (architecture is irrelevant): http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked Here's the answer in the bugtracker: https://bugs.funtoo.org/browse/FL-1491?focusedCommentId=18018&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-18018
 
Now libvirt seems to merge fine (still compiling, but no errors so far).
 
Thank you!

Hey, I wanted to let you know that I've fixed it by myself:
 
1. Remove berkdb USE from libetpan and emerge it: I did USE=-berkdb emerge -N libetpan.
2. Re-enable that USE and re-emerge the package: I did emerge -N libetpan.
 
Thanks!