stubs: Add arch_type

blockdev.c uses the arch_type constant, so before we can use the file in
tools (i.e. outside of the system emulator), we need to add a stub for
it. A new QEMU_ARCH_NONE is introduced for this case.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200224143008.13362-3-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

include/sysemu/arch_init.h

@@ -24,6 +24,8 @@ enum {
     QEMU_ARCH_NIOS2 = (1 << 17),
     QEMU_ARCH_HPPA = (1 << 18),
     QEMU_ARCH_RISCV = (1 << 19),
+
+    QEMU_ARCH_NONE = (1 << 31),
 };
 
 extern const uint32_t arch_type;

stubs/Makefile.objs

+stub-obj-y += arch_type.o
 stub-obj-y += bdrv-next-monitor-owned.o
 stub-obj-y += blk-commit-all.o
 stub-obj-y += blockdev-close-all-bdrv-states.o

stubs/arch_type.c

+#include "qemu/osdep.h"
+#include "sysemu/arch_init.h"
+
+const uint32_t arch_type = QEMU_ARCH_NONE;