tell people that esp8266 is no longer supported

Closes #1483

Author: larsks

ports/esp8266/Makefile

@@ -216,7 +216,8 @@ SRC_QSTR += $(SRC_C) $(SRC_COMMON_HAL_EXPANDED) $(SRC_SHARED_MODULE_EXPANDED) $(
 # Append any auto-generated sources that are needed by sources listed in SRC_QSTR
 SRC_QSTR_AUTO_DEPS +=
 
-all: $(BUILD)/libaxtls.a $(FWBIN)
+all:
+	@echo "CircuitPython 4.0.0 and later do not support esp8266 boards."
 
 CONFVARS_FILE = $(BUILD)/confvars