[source] build: move append-file to image-commands.mk

[LEDE Commits]

mkresin pushed a commit to source.git, branch master:
https://git.lede-project.org/aeba0fe466b5e850d0cf0697fc120070230d7831

commit aeba0fe466b5e850d0cf0697fc120070230d7831
Author: Joseph C. Lehner <joseph.c.lehner at gmail.com>
AuthorDate: Mon Jan 23 14:40:10 2017 +0100

    build: move append-file to image-commands.mk
    
    Move it append-file to image-commands.mk so that it can used by other
    targets as well.
    
    Signed-off-by: Joseph C. Lehner <joseph.c.lehner at gmail.com>
---
 include/image-commands.mk           | 4 ++++
 target/linux/ipq806x/image/Makefile | 4 ----
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/image-commands.mk b/include/image-commands.mk
index 04fa853..e0f2918 100644
--- a/include/image-commands.mk
+++ b/include/image-commands.mk
@@ -110,6 +110,10 @@ define Build/append-rootfs
 	dd if=$(IMAGE_ROOTFS) >> $@
 endef
 
+define Build/append-file
+	cat "$(1)" >> "$@"
+endef
+
 define Build/append-ubi
 	sh $(TOPDIR)/scripts/ubinize-image.sh \
 		$(if $(UBOOTENV_IN_UBI),--uboot-env) \
diff --git a/target/linux/ipq806x/image/Makefile b/target/linux/ipq806x/image/Makefile
index 3cc48bb..33dc31d 100644
--- a/target/linux/ipq806x/image/Makefile
+++ b/target/linux/ipq806x/image/Makefile
@@ -31,10 +31,6 @@ define Image/Build
 	dd if=$(KDIR)/root.$(1) of=$(BIN_DIR)/$(IMG_PREFIX)-$(1)-root.img bs=2k conv=sync
 endef
 
-define Build/append-file
-	cat $(1) >> $@
-endef
-
 define Device/Default
 	PROFILES := Default
 	KERNEL_DEPENDS = $$(wildcard $(DTS_DIR)/$$(DEVICE_DTS).dts)