For third party components (lwip and expat), compilation flags are adjusted to silence existing warnings (i have manually checked that all warnings are benign).
In components/esp32, replaced use of WIFI_DEBUG with ESP_LOG functions.
Only remaining warning is in FreeRTOS queue.c, and it may be a useful one.
Used by mbedTLS to set MBEDTLS_CONFIG_FILE in all components.
This change sets CFLAGS/etc at the project level and then exports those
variables for components, rather than setting them independently each time
a component Makefile is invoked.
Fixes problems with Eclipse trying to build in directories it shouldn't.
This is a breaking change for existing repositories, they need to rename
any component Makefiles to component.mk and rename their references to
$(IDF_PATH)/make/component.mk to $(IDF_PATH)/make/component_common.mk
