config-all-devices.mak: rebuild on reconfigure

This ensures that softmmu directories are culled after a
"./configure --target-list=x86_64-linux-user".

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Makefile

@@ -331,10 +331,10 @@ SUBDIR_DEVICES_MAK=$(patsubst %, %/config-devices.mak, $(filter %-softmmu, $(TAR
 SUBDIR_DEVICES_MAK_DEP=$(patsubst %, %.d, $(SUBDIR_DEVICES_MAK))
 
 ifeq ($(SUBDIR_DEVICES_MAK),)
-config-all-devices.mak:
+config-all-devices.mak: config-host.mak
 	$(call quiet-command,echo '# no devices' > $@,"GEN","$@")
 else
-config-all-devices.mak: $(SUBDIR_DEVICES_MAK)
+config-all-devices.mak: $(SUBDIR_DEVICES_MAK) config-host.mak
 	$(call quiet-command, sed -n \
              's|^\([^=]*\)=\(.*\)$$|\1:=$$(findstring y,$$(\1)\2)|p' \
              $(SUBDIR_DEVICES_MAK) | sort -u > $@, \