Add simple mongoose/esp32 example (w/out mOS)

PUBLISHED_FROM=0e407a2fb328107540d753123fe027f43860d0ef

examples/ESP32_IDF/Makefile

@@ -0,0 +1,16 @@
+SDK_VER=$(shell cat sdk.version)
+
+.PHONY: all
+
+MG_PATH = $(realpath $(PWD)/../../)
+
+all:
+	docker run --rm -it -v $(MG_PATH):/esp32_idf \
+                   $(SDK_VER) \
+                   bash -c "cd esp32_idf/examples/ESP32_IDF && \
+                   make -f Makefile.build defconfig && make -f Makefile.build"
+
+clean:
+	docker run --rm -it -v $(MG_PATH):/esp32_idf \
+                   $(SDK_VER) \
+                   bash -c "rm -rf esp32_idf/examples/ESP32_IDF/build"