added some windows/cmd.exe stuff

test/ref/Makefile

@@ -2,18 +2,27 @@
 # makefile for the regression tests that generate output which has to be
 # compared with reference output
 
+ifneq ($(shell echo),)
+  CMD_EXE = 1
+endif
+
 CC65FLAGS = -t sim6502
 SIM65FLAGS = -x 200000000
 
 CL65 := $(if $(wildcard ../../bin/cl65*),../../bin/cl65,cl65)
 SIM65 := $(if $(wildcard ../../bin/sim65*),../../bin/sim65,sim65)
 
+ifdef CMD_EXE
+RM := del /f
+DIFF := fc
+else
 RM := rm -f
 DIFF := diff -q
+endif
 
 CFLAGS := -O2 -Wall -W -Wextra -fwrapv -fno-strict-overflow
 
-.PHONY: all
+.PHONY: all clean
 
 REFS := $(patsubst %.c,%.ref,$(wildcard *.c))