Add Zephyr examples

examples/zephyr/websocket-server/Makefile

@@ -0,0 +1,16 @@
+CWD = $(realpath $(CURDIR))
+ZEPHYR_DIR ?= $(realpath ../../../../zephyrproject)
+BOARD ?= nucleo_h743zi
+
+example:
+	true
+
+build:
+	cp ../../../mongoose.c ../../../mongoose.h src/
+	cd $(ZEPHYR_DIR) && west build -b $(BOARD) -p auto $(CWD)
+
+flash:
+	cd $(ZEPHYR_DIR) && west flash
+
+clean:
+	rm -rf */*/mongoose.*