fs: declare phony targets as such

This commit improves the filesystem handling code to declare its
various targets as PHONY when appropriate.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

fs/common.mk

@@ -102,6 +102,8 @@ rootfs-$(1)-show-depends:
 
 rootfs-$(1): $$(BINARIES_DIR)/rootfs.$(1) $$(ROOTFS_$(2)_POST_TARGETS)
 
+.PHONY: rootfs-$(1) rootfs-$(1)-show-depends
+
 ifeq ($$(BR2_TARGET_ROOTFS_$(2)),y)
 TARGETS_ROOTFS += rootfs-$(1)
 endif

fs/ext2/ext2.mk

@@ -35,6 +35,8 @@ endef
 rootfs-ext2-symlink:
 	ln -sf rootfs.ext2$(ROOTFS_EXT2_COMPRESS_EXT) $(BINARIES_DIR)/rootfs.ext$(BR2_TARGET_ROOTFS_EXT2_GEN)$(ROOTFS_EXT2_COMPRESS_EXT)
 
+.PHONY: rootfs-ext2-symlink
+
 ifneq ($(BR2_TARGET_ROOTFS_EXT2_GEN),2)
 ROOTFS_EXT2_POST_TARGETS += rootfs-ext2-symlink
 endif

fs/initramfs/initramfs.mk

@@ -17,6 +17,8 @@ rootfs-initramfs: $(ROOTFS_INITRAMFS_DEPENDENCIES) $(ROOTFS_INITRAMFS_POST_TARGE
 rootfs-initramfs-show-depends:
 	@echo $(ROOTFS_INITRAMFS_DEPENDENCIES)
 
+.PHONY: rootfs-initramfs rootfs-initramfs-show-depends
+
 ifeq ($(BR2_TARGET_ROOTFS_INITRAMFS),y)
 TARGETS_ROOTFS += rootfs-initramfs
 endif

fs/iso9660/iso9660.mk

@@ -48,6 +48,8 @@ rootfs-iso9660: $(BINARIES_DIR)/rootfs.iso9660
 rootfs-iso9660-show-depends:
 	@echo $(ROOTFS_ISO9660_DEPENDENCIES)
 
+.PHONY: rootfs-iso9660 rootfs-iso9660-show-depends
+
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