Allow backports to be integrated into vmlinux with newer Makefiles

diff --git a/Makefile b/Makefile
index f5c8983..31c7cbf 100644
--- a/Makefile
+++ b/Makefile
@@ -555,6 +555,7 @@ scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \
 	$(Q)$(MAKE) $(build)=$(@)
 
 # Objects we will link into vmlinux / subdirs we need to visit
+backports-y 	:= backports/
 init-y		:= init/
 drivers-y	:= drivers/ sound/ firmware/
 net-y		:= net/
@@ -887,11 +888,13 @@ core-y		+= kernel/ mm/ fs/ ipc/ security/ crypto/ block/
 
 vmlinux-dirs	:= $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
 		     $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
+		     $(backports-y) $(backports-m) \
 		     $(net-y) $(net-m) $(libs-y) $(libs-m)))
 
 vmlinux-alldirs	:= $(sort $(vmlinux-dirs) $(patsubst %/,%,$(filter %/, \
-		     $(init-) $(core-) $(drivers-) $(net-) $(libs-))))
+		     $(init-) $(core-) $(drivers-) $(backports-) $(net-) $(libs-))))
 
+backports-y	:= $(patsubst %/, %/built-in.o, $(backports-y))
 init-y		:= $(patsubst %/, %/built-in.o, $(init-y))
 core-y		:= $(patsubst %/, %/built-in.o, $(core-y))
 drivers-y	:= $(patsubst %/, %/built-in.o, $(drivers-y))
@@ -902,7 +905,7 @@ libs-y		:= $(libs-y1) $(libs-y2)
 
 # Externally visible symbols (used by link-vmlinux.sh)
 export KBUILD_VMLINUX_INIT := $(head-y) $(init-y)
-export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y) $(drivers-y) $(net-y)
+export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y) $(drivers-y) $(net-y) $(backports-y)
 export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
 export LDFLAGS_vmlinux
 # used by scripts/pacmage/Makefile