Merge branch 'The-OpenROAD-Project:master' into tighten_rules_tns_100_pin_swap2

Author: openroadie

flow/platforms/asap7/config.mk

@@ -115,9 +115,9 @@ export TAP_CELL_NAME           = TAPCELL_ASAP7_75t_R
 export SET_RC_TCL              = $(PLATFORM_DIR)/setRC.tcl
 
 # Route options
-export MIN_ROUTING_LAYER       = M2
+export MIN_ROUTING_LAYER       ?= M2
 #export MIN_CLOCK_ROUTING_LAYER = M4
-export MAX_ROUTING_LAYER       = M7
+export MAX_ROUTING_LAYER       ?= M7
 
 # KLayout technology file
 export KLAYOUT_TECH_FILE       = $(PLATFORM_DIR)/KLayout/asap7.lyt