build: remove extra-obj-y

extra-obj-y is somewhat complicated to understand.  Replace it with a
special CONFIG_ALL symbol that is defined only at toplevel.
This limits the case of directories defining more than one
*-obj-y target.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

Makefile

@@ -105,6 +105,7 @@ defconfig:
 -include config-all-disas.mak
 CONFIG_SOFTMMU := $(if $(filter %-softmmu,$(TARGET_DIRS)),y)
 CONFIG_USER_ONLY := $(if $(filter %-user,$(TARGET_DIRS)),y)
+CONFIG_ALL=y
 
 ifneq ($(wildcard config-host.mak),)
 include $(SRC_PATH)/Makefile.objs
@@ -135,7 +136,7 @@ pixman/Makefile: $(SRC_PATH)/pixman/configure
 $(SRC_PATH)/pixman/configure:
 	(cd $(SRC_PATH)/pixman; autoreconf -v --install)
 
-$(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y) $(extra-obj-y)
+$(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y)
 
 ROMSUBDIR_RULES=$(patsubst %,romsubdir-%, $(ROMS))
 romsubdir-%:

Makefile.objs

@@ -55,7 +55,6 @@ common-obj-$(CONFIG_WIN32) += os-win32.o
 common-obj-$(CONFIG_POSIX) += os-posix.o
 
 common-obj-$(CONFIG_LINUX) += fsdev/
-extra-obj-$(CONFIG_LINUX) += fsdev/
 
 common-obj-y += migration.o migration-tcp.o
 common-obj-y += qemu-char.o #aio.o
@@ -68,7 +67,6 @@ common-obj-$(CONFIG_SPICE) += spice-qemu-char.o
 
 common-obj-y += audio/
 common-obj-y += hw/
-extra-obj-y += hw/
 
 common-obj-y += ui/
 common-obj-y += bt-host.o bt-vhci.o
@@ -118,6 +116,5 @@ nested-vars += \
 	util-obj-y \
 	qga-obj-y \
 	block-obj-y \
-	common-obj-y \
-	extra-obj-y
+	common-obj-y
 dummy := $(call unnest-vars)

fsdev/Makefile.objs

@@ -1,10 +1,10 @@
 ifeq ($(CONFIG_REALLY_VIRTFS),y)
 common-obj-y = qemu-fsdev.o virtio-9p-marshal.o
-
-# Toplevel always builds this; targets without virtio will put it in
-# common-obj-y
-extra-obj-y = qemu-fsdev-dummy.o
 else
 common-obj-y = qemu-fsdev-dummy.o
 endif
 common-obj-y += qemu-fsdev-opts.o
+
+# Toplevel always builds this; targets without virtio will put it in
+# common-obj-y
+common-obj-$(CONFIG_ALL) += qemu-fsdev-dummy.o

hw/Makefile.objs

@@ -44,8 +44,6 @@ common-obj-$(CONFIG_I8259) += i8259_common.o i8259.o
 common-obj-y += fifo.o
 common-obj-y += pam.o
 
-extra-obj-y += pci/
-
 # PPC devices
 common-obj-$(CONFIG_PREP_PCI) += prep_pci.o
 common-obj-$(CONFIG_I82378) += i82378.o

hw/pci/Makefile.objs

@@ -6,4 +6,4 @@ common-obj-$(CONFIG_PCI) += pci_host.o pcie_host.o
 common-obj-$(CONFIG_PCI) += pcie.o pcie_aer.o pcie_port.o
 common-obj-$(CONFIG_NO_PCI) += pci-stub.o
 
-extra-obj-y += pci-stub.o
+common-obj-$(CONFIG_ALL) += pci-stub.o