export PDKPATH for running precheck

Makefile

diff --git a/Makefile b/Makefile
index ccc8a6d..22b011e 100644
--- a/Makefile
+++ b/Makefile
@@ -19,6 +19,7 @@
 SIM ?= RTL
 
 export OPEN_PDKS_COMMIT?=7519dfb04400f224f140749cda44ee7de6f5e095
+export PDKPATH?=$(PDK_ROOT)/sky130A
 # Install lite version of caravel, (1): caravel-lite, (0): caravel
 CARAVEL_LITE?=1
 
@@ -110,8 +111,14 @@
 run-precheck: check-pdk check-precheck
 	$(eval INPUT_DIRECTORY := $(shell pwd))
 	cd $(PRECHECK_ROOT) && \
-	docker run -v $(PRECHECK_ROOT):$(PRECHECK_ROOT) -v $(INPUT_DIRECTORY):$(INPUT_DIRECTORY) -v $(PDK_ROOT):$(PDK_ROOT) -e INPUT_DIRECTORY=$(INPUT_DIRECTORY) -e PDK_ROOT=$(PDK_ROOT) \
-	-u $(shell id -u $(USER)):$(shell id -g $(USER)) efabless/mpw_precheck:latest bash -c "cd $(PRECHECK_ROOT) ; python3 mpw_precheck.py --input_directory $(INPUT_DIRECTORY) --pdk_root $(PDK_ROOT)"
+	docker run -v $(PRECHECK_ROOT):$(PRECHECK_ROOT) \
+	-v $(INPUT_DIRECTORY):$(INPUT_DIRECTORY) \
+	-v $(PDK_ROOT):$(PDK_ROOT) \
+	-e INPUT_DIRECTORY=$(INPUT_DIRECTORY) \
+	-e PDK_ROOT=$(PDK_ROOT) \
+	-e PDKPATH=$(PDKPATH) \
+	-u $(shell id -u $(USER)):$(shell id -g $(USER)) \
+	efabless/mpw_precheck:latest bash -c "cd $(PRECHECK_ROOT) ; python3 mpw_precheck.py --input_directory $(INPUT_DIRECTORY) --pdk_root $(PDK_ROOT)"
 
 # Clean 
 .PHONY: clean