Use $< to refer to the first prerequisite listed in the rule

Makefile

@@ -787,10 +787,10 @@ abc/abc$(EXE) abc/libabc.a: $(ABC_SOURCES)
 	$(Q) mkdir -p abc && $(MAKE) -C $(PROGRAM_PREFIX)abc -f "$(realpath $(YOSYS_SRC)/abc/Makefile)" ABCSRC="$(realpath $(YOSYS_SRC)/abc/)" $(S) $(ABCMKARGS) $(if $(filter %.a,$@),PROG="abc",PROG="abc$(EXE)") MSG_PREFIX="$(eval P_OFFSET = 5)$(call P_SHOW)$(eval P_OFFSET = 10) ABC: " $(if $(filter %.a,$@),libabc.a)
 
 $(PROGRAM_PREFIX)yosys-abc$(EXE): abc/abc$(EXE)
-	$(P) cp abc/abc$(EXE) $(PROGRAM_PREFIX)yosys-abc$(EXE)
+	$(P) cp $< $(PROGRAM_PREFIX)yosys-abc$(EXE)
 
 $(PROGRAM_PREFIX)yosys-libabc.a: abc/libabc.a
-	$(P) cp abc/libabc.a $(PROGRAM_PREFIX)yosys-libabc.a
+	$(P) cp $< $(PROGRAM_PREFIX)yosys-libabc.a
 
 ifneq ($(SEED),)
 SEEDOPT="-S $(SEED)"