Move KVM and Xen global flags to vl.c

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/vl.c b/vl.c
index a2869b8..d9fc0cc 100644
--- a/vl.c
+++ b/vl.c
@@ -258,6 +258,10 @@
 static QEMUBootSetHandler *boot_set_handler;
 static void *boot_set_opaque;
 
+int kvm_allowed = 0;
+uint32_t xen_domid;
+enum xen_mode xen_mode = XEN_EMULATE;
+
 #ifdef SIGRTMIN
 #define SIG_IPI (SIGRTMIN+4)
 #else