# directory, so it can be displayed as if it were a relative directory. Take
# just one argument, the file name.
abbr_helper = $(subst $T,.,$(patsubst $T/%,%,$1))
-abbr = $(if $(call eq,$(call abbr_helper,$1),$1),$1, \
- $(addprefix $(shell echo $R | sed 's|/\?\([^/]\+\)/\?|../|g'),\
+abbr = $(if $(call eq,$(call abbr_helper,$1),$1),$1,$(addprefix \
+ $(shell echo $R | sed 's|/\?\([^/]\+\)/\?|../|g'),\
$(call abbr_helper,$1)))
# Execute a command printing a nice message if $V is @.