makefile: move more synth vars to config.sh

Signed-off-by: Øyvind Harboe <[email protected]>

Author: oharboe

flow/Makefile

@@ -331,10 +331,6 @@ memory:
 
 # Run Synthesis using yosys
 #-------------------------------------------------------------------------------
-
-export SYNTH_SCRIPT ?= $(SCRIPTS_DIR)/synth.tcl
-export SDC_FILE_CLOCK_PERIOD = $(RESULTS_DIR)/clock_period.txt
-
 $(SDC_FILE_CLOCK_PERIOD): $(SDC_FILE)
 	mkdir -p $(dir $@)
 	echo $(ABC_CLOCK_PERIOD_IN_PS) > $@

flow/scripts/config.sh

@@ -110,3 +110,6 @@ export KLAYOUT_CMD
 if command -v stdbuf &>/dev/null; then
   export STDBUF_CMD="stdbuf -o L"
 fi
+
+export SYNTH_SCRIPT="${SYNTH_SCRIPT:-${SCRIPTS_DIR}/synth.tcl}"
+export SDC_FILE_CLOCK_PERIOD="${SDC_FILE_CLOCK_PERIOD:-${RESULTS_DIR}/clock_period.txt}"