Add KEPLER_FORMAL_EXE env

Signed-off-by: nanocoh <noam.chn1@gmail.com>

Author: Noam Cohen

flow/scripts/lec_check.tcl

@@ -23,7 +23,7 @@ proc write_lec_script { step file1 file2 } {
 proc run_lec_test { step file1 file2 } {
   write_lec_script $step $file1 $file2
   # tclint-disable-next-line command-args
-  eval exec kepler-formal --config $::env(OBJECTS_DIR)/${step}_lec_test.yml
+  eval exec $::env(KEPLER_FORMAL_EXE) --config $::env(OBJECTS_DIR)/${step}_lec_test.yml
   try {
     set count [exec grep -c "Found difference" $::env(LOG_DIR)/${step}_lec_check.log]]
   } trap CHILDSTATUS {results options} {

flow/scripts/variables.mk

@@ -117,6 +117,9 @@ YOSYS_IS_VALID := $(if $(YOSYS_EXE),$(shell test -x $(YOSYS_EXE) && echo "true")
 KLAYOUT_DIR = $(abspath $(FLOW_HOME)/../tools/install/klayout/)
 KLAYOUT_BIN_FROM_DIR = $(KLAYOUT_DIR)/klayout
 
+KEPLER_FORMAL_EXE ?= $(abspath $(FLOW_HOME)/../tools/install/kepler-formal/bin/kepler-formal)
+export KEPLER_FORMAL_EXE := $(KEPLER_FORMAL_EXE)
+
 ifeq ($(wildcard $(KLAYOUT_BIN_FROM_DIR)), $(KLAYOUT_BIN_FROM_DIR))
 export KLAYOUT_CMD ?= sh -c 'LD_LIBRARY_PATH=$(dir $(KLAYOUT_BIN_FROM_DIR)) $$0 "$$@"' $(KLAYOUT_BIN_FROM_DIR)
 else