ulp: add build system integration and example

examples/system/ulp/main/component.mk

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+
+
+#
+# ULP support additions to component makefile.
+#
+# 1. ULP_APP_NAME must be unique (if multiple components use ULP)
+#    Default value, override if necessary:
+ULP_APP_NAME ?= ulp_$(COMPONENT_NAME)
+#
+# 2. Specify all assembly source files here.
+#    Files should be placed into a separate directory (in this case, ulp/),
+#    which should not be added to COMPONENT_SRCDIRS.
+ULP_S_SOURCES = $(addprefix $(COMPONENT_PATH)/ulp/, \
+	pulse_cnt.S \
+	)
+#
+# 3. List all the component object files which include automatically
+#    generated ULP export file, $(ULP_APP_NAME).h:
+ULP_EXP_DEP_OBJECTS := ulp_example_main.o
+#
+# 4. Include build rules for ULP program 
+include $(IDF_PATH)/components/ulp/component_ulp_common.mk
+#
+# End of ULP support additions to component makefile.
+#