arm-autonomy: qemu: Split qemu into qemu and qemu-xen packages

When xen is in DISTRO_FEATURES we split the qemu package and install
only the qemu-xen with /usr/bin/qemu-system-i386 binary in the image
to reduce its size.

Change-Id: I460e959eb87a180b1baa5a11dbbe7df100d5e6a6
Issue-Id: SCM-813
Signed-off-by: Diego Sueiro <diego.sueiro@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-autonomy/recipes-core/images/arm-autonomy-host-image-minimal.bb

@@ -39,7 +39,7 @@ IMAGE_INSTALL += " \
     packagegroup-core-boot \
     packagegroup-core-ssh-openssh \
     kernel-modules \
-    qemu \
+    qemu-xen \
     xenguest-manager \
     xenguest-network-bridge \
     "

meta-arm-autonomy/recipes-devtools/qemu/qemu_%.bbappend

@@ -0,0 +1,16 @@
+# Use OVERRIDES to minimize the usage of
+# ${@bb.utils.contains('DISTRO_FEATURES', 'xen', ...
+OVERRIDES_append = "${@bb.utils.contains('DISTRO_FEATURES', 'xen', ':xen', '', d)}"
+
+# For Xen we only need the i386 binaries
+QEMU_TARGETS_xen = "i386"
+PACKAGECONFIG_append_xen = " virtfs"
+PACKAGECONFIG_remove_xen = "sdl"
+
+# Reduce the qemu package size by splitting it into
+# qemu and qemu-xen packages
+PACKAGES_prepend_xen := "${PN}-xen"
+RDEPENDS_${PN}_xen += "${PN}-xen"
+FILES_${PN}-xen_xen = "${bindir}/qemu-system-i386"
+RDEPENDS_${PN}-xen_xen += "xen-tools-libxenstore xen-tools-libxenctrl \
+    xen-tools-libxenguest"