+# Execute commands under flock
+# $(1) => The shell expression.
+# $(2) => The lock name. If not given, the global lock will be used.
+ifneq ($(wildcard $(STAGING_DIR_HOST)/bin/flock),)
+ define locked
+ SHELL= \
+ flock \
+ $(TMP_DIR)/.$(if $(2),$(strip $(2)),global).flock \
+ -c '$(subst ','\'',$(1))'
+ endef
+else
+ locked=$(1)
+endif
+
+# Recursively copy paths into another directory, purge dangling
+# symlinks before.
+# $(1) => File glob expression
+# $(2) => Destination directory
+define file_copy
+ for src_dir in $(sort $(foreach d,$(wildcard $(1)),$(dir $(d)))); do \
+ ( cd $$src_dir; find -type f -or -type d ) | \
+ ( cd $(2); while :; do \
+ read FILE; \
+ [ -z "$$FILE" ] && break; \
+ [ -L "$$FILE" ] || continue; \
+ echo "Removing symlink $(2)/$$FILE"; \
+ rm -f "$$FILE"; \
+ done; ); \
+ done; \
+ $(CP) $(1) $(2)
+endef
+