Makefile: introduce common-obj-m and block-obj-m for DSO

$(common-obj-m) will include $(block-obj-m), like $(common-obj-y) does
for $(block-obj-y).
Signed-off-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Makefile

@@ -129,7 +129,9 @@ dummy := $(call unnest-vars,, \
                 util-obj-y \
                 qga-obj-y \
                 block-obj-y \
-                common-obj-y)
+                block-obj-m \
+                common-obj-y \
+                common-obj-m)
 
 ifneq ($(wildcard config-host.mak),)
 include $(SRC_PATH)/tests/Makefile

Makefile.objs

@@ -19,6 +19,8 @@ block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
 block-obj-y += qemu-coroutine-sleep.o
 block-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
 
+block-obj-m = block/
+
 ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)
 # Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.
 # only pull in the actual virtio-9p device if we also enabled virtio.

Makefile.target

@@ -148,7 +148,11 @@ obj-y-save := $(obj-y)
 block-obj-y :=
 common-obj-y :=
 include $(SRC_PATH)/Makefile.objs
-dummy := $(call unnest-vars,..,block-obj-y common-obj-y)
+dummy := $(call unnest-vars,.., \
+               block-obj-y \
+               block-obj-m \
+               common-obj-y \
+               common-obj-m)
 
 # Now restore obj-y
 obj-y := $(obj-y-save)