kbuild: Nicer warnings

Improve the warning messages when using obsolete features, kill one
remaining user of $(list-multi)

(by Sam Ravnborg)

I also made O_TARGET != built-in.o an error, since compatibility code for
that case has already been dropped 

Rules.make

@@ -12,17 +12,17 @@ space   := $(empty) $(empty)
 # ---------------------------------------------------------------------------
 
 ifdef O_TARGET
-$(warning kbuild: Usage of O_TARGET is obsolete in 2.5. Please fix!
+$(error kbuild: $(obj)/Makefile - Usage of O_TARGET := $(O_TARGET) is obsolete in 2.5. Please fix!
 endif
 
 ifdef L_TARGET
 ifneq ($(L_TARGET),lib.a)
-$(warning kbuild: L_TARGET ($(L_TARGET)) should be renamed to lib.a. Please fix!)
+$(warning kbuild: $(obj)/Makefile - L_TARGET := $(L_TARGET) target shall be renamed to lib.a. Please fix!)
 endif
 endif
 
 ifdef list-multi
-$(warning kbuild: list-multi ($(list-multi)) is obsolete in 2.5. Please fix!)
+$(warning kbuild: $(obj)/Makefile - list-multi := $(list-multi) is obsolete in 2.5. Please fix!)
 endif
 
 # Some paths for the Makefiles to use

drivers/input/joystick/iforce/Makefile

@@ -5,7 +5,6 @@
 #
 
 # Goal definition
-list-multi	:= iforce.o
 iforce-objs	:= iforce-ff.o iforce-main.o iforce-packets.o
 
 obj-$(CONFIG_JOYSTICK_IFORCE)	+= iforce.o 
@@ -23,8 +22,3 @@ EXTRA_CFLAGS = -Werror-implicit-function-declaration
 # The global Rules.make.
 
 include $(TOPDIR)/Rules.make
-
-# Additional rules
-iforce.o: $(iforce-objs)
-	$(LD) -r -o $@ $(iforce-objs)
-