make: automatically include dependencies in recursive subdir rules (v2)

I think I understand enough of what's going on in these rules to ensure this is
right.  But I could certainly use a second or third opinion...

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

Makefile

@@ -406,5 +406,5 @@ tar:
 Makefile: $(GENERATED_HEADERS)
 
 # Include automatically generated dependency files
--include $(wildcard *.d audio/*.d slirp/*.d block/*.d net/*.d ui/*.d qapi/*.d)
--include $(wildcard qga/*.d hw/*.d hw/usb/*.d)
+# All subdir dependencies come automatically from our recursive subdir rules
+-include $(wildcard *.d)

Makefile.dis

@@ -20,4 +20,4 @@ clean:
 	rm -f *.o *.d *.a *~
 
 # Include automatically generated dependency files
--include $(wildcard *.d */*.d)
+-include $(wildcard *.d)

Makefile.target

@@ -216,4 +216,4 @@ GENERATED_HEADERS += config-target.h
 Makefile: $(GENERATED_HEADERS)
 
 # Include automatically generated dependency files
--include $(wildcard *.d */*.d)
+-include $(wildcard *.d)

Makefile.user

@@ -23,4 +23,4 @@ clean:
 	done
 
 # Include automatically generated dependency files
--include $(wildcard *.d */*.d)
+-include $(wildcard *.d)

hw/i386/Makefile.objs

@@ -7,7 +7,7 @@ obj-y += debugcon.o multiboot.o
 obj-y += pc_piix.o
 obj-y += pc_sysfw.o
 obj-$(CONFIG_XEN) += xen_platform.o xen_apic.o
-obj-$(CONFIG_KVM) += kvm/clock.o kvm/apic.o kvm/i8259.o kvm/ioapic.o kvm/i8254.o
+obj-y += kvm/
 obj-$(CONFIG_SPICE) += qxl.o qxl-logger.o qxl-render.o
 
 obj-y := $(addprefix ../,$(obj-y))

hw/kvm/Makefile.objs

@@ -0,0 +1 @@
+obj-$(CONFIG_KVM) += clock.o apic.o i8259.o ioapic.o i8254.o

rules.mak

@@ -94,6 +94,7 @@ define unnest-dir
 $(foreach var,$(nested-vars),$(call push-var,$(var),$1/))
 $(eval obj := $(obj)/$1)
 $(eval include $(SRC_PATH)/$1/Makefile.objs)
+$(eval -include $(wildcard $1/*.d))
 $(eval obj := $(patsubst %/$1,%,$(obj)))
 $(foreach var,$(nested-vars),$(call pop-var,$(var),$1/))
 endef