As part of the big modularizing efforts of the Arduino project they
split out the hardware-independent layer of the Arduino "language"
from the hardware-specific cores into the dedicated 'ArduinoCore-API'
repository. As described in 'ArduinoCore-API's README, the API source
files won't reside directly in the directory of the standard Arduino
core, i.e. in 'ARDUINO_CORE_PATH', but in its 'ARDUINO_CORE_PATH/api'
subdirectory. Consequently, Arduino-Makefile won't be able to build
any projects when using an Arduino core following the new directory
structure.
Prepare for the upcoming new Arduino core directory structure by
building all 'ARDUINO_CORE_PATH/api/*.cpp' source files as well. Out
of caution, look out for and build any .c source files in that
directory, too: though there are no .c source files in the
'ArduinoCore-API' repository at the moment, in the future there might
be. Furthermore, add this directory to the list of directories to be
searched for header files: though it's not necessary to explicitly and
directly include any header file from this directory ('Arduino.h'
includes all there is), some projects might nonetheless do so, and
their build would then break.
Note that a 'make clean' will be most likely necessary when
re-building a project after switching to the new directory structure.
There is a bit of inconsistency between documentation and code
regarding the ARDUINO_QUIET variable: 'arduino-mk-vars.md' states
that ARDUINO_QUIET "Defaults to `0` (unset/disabled)", but the code
only checks whether it's defined or not, and doesn't check whether
it's set to '0' or something else.
Consequently, having 'ARDUINO_QUIET=0' in the Makefile or running
'make ARDUINO_QUIET=0' contadicts the documentation and doesn't print
the configuration. It also means that if someone in general prefers
not to see a screenful of configuration on each build and therefore
has 'ARDUINO_QUIET = 1' in the project's Makefile or 'config.mak',
then there is no way to override it from the command line in the odd
case when showing the configuration is desired.
Modify the corresponding condition in Arduino.mk to check whether
ARDUINO_QUIET is set to 0 and treat an undefined ARDUINO_QUIET
variable as "set to 0" as well.
`avr-size` was defaulting to AVR non-aware when using ARM builds, which
meant passing .hex rather than .elf to size and limiting size readout.
Adding a switch for defining `avr-size` and SIZEFLAGS to Sam.mk seems
like the best way to include proper ARM support (despite conflicting
naming).
