lint targets should depend on the lint script itself

Makefile

@@ -62,6 +62,7 @@ NONGEN_CXX_SRCS := $(shell find \
 	examples \
 	tools \
 	-name "*.cpp" -or -name "*.hpp" -or -name "*.cu" -or -name "*.cuh")
+LINT_SCRIPT := scripts/cpp_lint.py
 LINT_OUTPUT_DIR := $(BUILD_DIR)/.lint
 LINT_EXT := lint.txt
 LINT_OUTPUTS := $(addsuffix .$(LINT_EXT), $(addprefix $(LINT_OUTPUT_DIR)/, $(NONGEN_CXX_SRCS)))
@@ -322,9 +323,9 @@ $(EMPTY_LINT_REPORT): $(LINT_OUTPUTS) | $(BUILD_DIR)
 	  $(RM) $(NONEMPTY_LINT_REPORT); \
 	  echo "No lint errors!";
 
-$(LINT_OUTPUTS): $(LINT_OUTPUT_DIR)/%.lint.txt : % | $(LINT_OUTPUT_DIR)
+$(LINT_OUTPUTS): $(LINT_OUTPUT_DIR)/%.lint.txt : % $(LINT_SCRIPT) | $(LINT_OUTPUT_DIR)
 	@ mkdir -p $(dir $@)
-	@ python ./scripts/cpp_lint.py $< 2>&1 \
+	@ python $(LINT_SCRIPT) $< 2>&1 \
 		| grep -v "^Done processing " \
 		| grep -v "^Total errors found: 0" \
 		> $@ \