error: Link qemu-img, qemu-nbd, qemu-io with qemu-error.o

The location tracking interface is used by code shared with qemi-img,
qemu-nbd and qemu-io, so it needs to be available there.  Commit
827b0813 provides it in a rather hamfisted way: it adds a dummy
implementation to qemu-tool.c.

It's cleaner to provide the real thing, and put a few more dummy
monitor functions into qemu-tool.c.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/Makefile b/Makefile
index 57c354d..a404fda 100644
--- a/Makefile
+++ b/Makefile
@@ -129,11 +129,11 @@
 qemu-img.o: qemu-img-cmds.h
 qemu-img.o qemu-tool.o qemu-nbd.o qemu-io.o: $(GENERATED_HEADERS)
 
-qemu-img$(EXESUF): qemu-img.o qemu-tool.o $(block-obj-y) $(qobject-obj-y)
+qemu-img$(EXESUF): qemu-img.o qemu-tool.o qemu-error.o $(block-obj-y) $(qobject-obj-y)
 
-qemu-nbd$(EXESUF): qemu-nbd.o qemu-tool.o $(block-obj-y) $(qobject-obj-y)
+qemu-nbd$(EXESUF): qemu-nbd.o qemu-tool.o qemu-error.o $(block-obj-y) $(qobject-obj-y)
 
-qemu-io$(EXESUF): qemu-io.o qemu-tool.o cmd.o $(block-obj-y) $(qobject-obj-y)
+qemu-io$(EXESUF): qemu-io.o cmd.o qemu-tool.o qemu-error.o $(block-obj-y) $(qobject-obj-y)
 
 qemu-img-cmds.h: $(SRC_PATH)/qemu-img-cmds.hx
 	$(call quiet-command,sh $(SRC_PATH)/hxtool -h < $< > $@,"  GEN   $@")