Support building qemux86-64 to support the x86 SDK

Change-Id: I76d9bf89fc76037066ae01f36e42faae9e6f6dec
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/build-setup.sh b/build-setup.sh
index 6c0b3db..2251395 100755
--- a/build-setup.sh
+++ b/build-setup.sh
@@ -34,7 +34,7 @@
 #                     fedora: 23|24|25
 #                     Default: "latest"
 #  target             The target we aim to build:
-#                     evb-ast2500|palmetto|qemu
+#                     evb-ast2500|palmetto|qemu|qemux86-64
 #                     romulus|s2600wf|witherspoon|zaius
 #                     Default: "qemu"
 #
@@ -152,6 +152,9 @@
   qemu)
     LAYER_DIR="meta-phosphor"
     ;;
+  qemux86-64)
+    BITBAKE_CMD="MACHINE=qemux86-64 source oe-init-build-env"
+    ;;
   *)
     exit 1
     ;;