$ equery u qemu
-accessibility
+aio
+alsa
+bluetooth
+bzip2
+caps
+curl
-debug
+fdt
+filecaps
-gnutls
+gtk
-gtk2
-infiniband
-iscsi
+jpeg
-lzo
+ncurses
-nfs
+nls
-numa
+opengl
+pin-upstream-blobs
+png
-pulseaudio
-python
+python_targets_python2_7
-qemu_softmmu_targets_aarch64
-qemu_softmmu_targets_alpha
-qemu_softmmu_targets_arm
-qemu_softmmu_targets_cris
-qemu_softmmu_targets_i386
-qemu_softmmu_targets_lm32
-qemu_softmmu_targets_m68k
-qemu_softmmu_targets_microblaze
-qemu_softmmu_targets_microblazeel
-qemu_softmmu_targets_mips
-qemu_softmmu_targets_mips64
-qemu_softmmu_targets_mips64el
-qemu_softmmu_targets_mipsel
-qemu_softmmu_targets_moxie
-qemu_softmmu_targets_nios2
-qemu_softmmu_targets_or1k
-qemu_softmmu_targets_ppc
-qemu_softmmu_targets_ppc64
-qemu_softmmu_targets_ppcemb
-qemu_softmmu_targets_s390x
-qemu_softmmu_targets_sh4
-qemu_softmmu_targets_sh4eb
-qemu_softmmu_targets_sparc
-qemu_softmmu_targets_sparc64
-qemu_softmmu_targets_tricore
-qemu_softmmu_targets_unicore32
+qemu_softmmu_targets_x86_64
-qemu_softmmu_targets_xtensa
-qemu_softmmu_targets_xtensaeb
-qemu_user_targets_aarch64
-qemu_user_targets_alpha
-qemu_user_targets_arm
-qemu_user_targets_armeb
-qemu_user_targets_cris
-qemu_user_targets_hppa
-qemu_user_targets_i386
-qemu_user_targets_m68k
-qemu_user_targets_microblaze
-qemu_user_targets_microblazeel
-qemu_user_targets_mips
-qemu_user_targets_mips64
-qemu_user_targets_mips64el
-qemu_user_targets_mipsel
-qemu_user_targets_mipsn32
-qemu_user_targets_mipsn32el
-qemu_user_targets_nios2
-qemu_user_targets_or1k
-qemu_user_targets_ppc
-qemu_user_targets_ppc64
-qemu_user_targets_ppc64abi32
-qemu_user_targets_ppc64le
-qemu_user_targets_s390x
-qemu_user_targets_sh4
-qemu_user_targets_sh4eb
-qemu_user_targets_sparc
-qemu_user_targets_sparc32plus
-qemu_user_targets_sparc64
-qemu_user_targets_tilegx
+qemu_user_targets_x86_64
-rbd
-sasl
+sdl
-sdl2
+seccomp
-smartcard
-snappy
+spice
-ssh
-static
-static-user
-systemtap
-tci
-test
+usb
-usbredir
-vde
+vhost-net
-virgl
-virtfs
+vnc
-vte
+xattr
-xen
-xfs