software: add minimal xilinx library makefile

litex/soc/software/libxil/Makefile

@@ -0,0 +1,31 @@
+include ../include/generated/variables.mak
+include $(SOC_DIRECTORY)/software/common.mak
+
+all: libxil.a
+
+CFLAGS += -nostartfiles
+
+OBJECTS = xil_cache.o \
+	xil_exception.o \
+	asm_vectors.o \
+	boot.o \
+	cpu_init.o \
+	translation_table.o \
+	xil-crt0.o \
+	vectors.o \
+	xtime_l.o
+
+libxil.a: $(OBJECTS)
+	$(AR) crs $@ $^
+
+%.o: embeddedsw/lib/bsp/standalone/src/arm/cortexa9/%.c
+	$(compile)
+
+%.o: embeddedsw/lib/bsp/standalone/src/arm/common/%.c
+	$(compile)
+
+%.o: embeddedsw/lib/bsp/standalone/src/arm/cortexa9/gcc/%.S
+	$(assemble)
+
+clean:
+	$(RM) $(OBJECTS) libxil.a