* Philosophical: "explicit is better than implicit".
* Practical: Allows useful errors if invalid directories given in components as the defaults aren't
always used. Also trims the -I path from a number of components that have no actual include
directory.
* Simplifies knowing which components will be header-only and which won't
Default esp-idf builds now show -Wextra warnings (except for a few:
signed/unsigned comparison, unused parameters, old-style C declarations.)
CI building of examples runs with that level raised to -Werror, to catch
those changes going into the main repo.
New makefile component_wrapper.mk allows some variables to be set
before component.mk is evaluated. This properly fixes problems with
sdkconfig being hard to access in all phases of the build.
Including component_common.mk is no longer necessary and will print a
deprecation warning for components which use it.
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.
