make: load only required dependency files.

The old rules.mak loads dependency .d files using include directive
with file glob pattern "*.d". This breaks the build when build tree has
left-over *.d files from another build.

This patch fixes this by
  - loading precise list of .d files made from *.o and *.mo.
  - specifying explicit list of required dependency info files for
     *.hex autogenerated sources.

Note that Makefile still includes some .d in root directory by including
"*.d".

Signed-off-by: Victor Kaplansky <victork@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/Makefile.objs

@@ -7,8 +7,14 @@ obj-$(CONFIG_XEN) += ../xenpv/ xen/
 
 obj-y += kvmvapic.o
 obj-y += acpi-build.o
+
+gen-hex-y += hw/i386/acpi-dsdt.hex
+gen-hex-y += hw/i386/q35-acpi-dsdt.hex
+
 hw/i386/acpi-build.o: hw/i386/acpi-build.c \
-	hw/i386/acpi-dsdt.hex hw/i386/q35-acpi-dsdt.hex
+	$(gen-hex-y)
+
+-include $(gen-hex-y:.hex=.d)
 
 iasl-option=$(shell if test -z "`$(1) $(2) 2>&1 > /dev/null`" \
     ; then echo "$(2)"; else echo "$(3)"; fi ;)

rules.mak

@@ -368,6 +368,6 @@ define unnest-vars
                 $(error $o added in $v but $o-objs is not set)))
         $(shell mkdir -p ./ $(sort $(dir $($v))))
         # Include all the .d files
-        $(eval -include $(addsuffix *.d, $(sort $(dir $($v)))))
+        $(eval -include $(patsubst %.o,%.d,$(patsubst %.mo,%.d,$($v))))
         $(eval $v := $(filter-out %/,$($v))))
 endef