drivers/ethos: remove unnecessary casts.

ipv6_ext_rh: define type numbers at central place

Update Jiminy doc.txt

Added explanation for fuse settings.
Brown-out when 1.8V is set as system voltage.
Power increase in deep sleep when ext. xtal as system clock.

boards: Enable STM32F103C8 ROM hack via env var

emb6_sock_udp: copy receive remote correctly

test: trickle: fix condition for success

The `src` member of `sock_udp_t` for `emb6` is a pointer, not a value,
so it should not be referenced.

This fixes the output issue encountered during the
[2018.10 RC1 testing][RC1].

[RC1]: https://github.com/RIOT-OS/Release-Specs/issues/76#issuecomment-435924505

boards/msba2: Added call to periph_init

The current test implementation wrongly assumes that the diff between
two fired events (e1, e2) must always increase. That is not true, as
event e1 may reside on the upper part of [I/2, I) and e2 on the lower
part of [I, 2*I).

This commit fixes the test to look at the actual time that was randonmly
chosen from both intervals (t1, t2). Given that the intervals are
doubled, t1 must always be smaller than t2.

cpu/esp32: doxygen fix for periph/gpio

cpu/esp8266: doxygen fix for periph/gpio

The STM32F103C8 secretly comes with 128KiB flash instead of 64KiB. Still, only
64KiB of it are tested and guaranteed to work. However, most of the times the
whole 128KiB flash works just fine. In the BluePill documentation this fact is
already documented and by using

    $ make BOARD=bluepill CPU_MODEL=stm32f103cb

the whole 128 KiB can be used by RIOT. When using this hack routinely, it easier
to use environment variables instead. But allowing to overwrite CPU_MODEL via
environment variables seems to be a bad thing, as it is easy to forget to clear
that environment variable when changing the BOARD variable.

This commit introduces the new STM32F103C8_FLASH_HACK variable, which unlocks
the 128KiB FLASH when set to "1". The BluePill documentation has been updated
accordingly.

sys/auto_init: Fixed initialization of sht1x [backport 2018.10]

Removes architecture specific includes from documentation of module  Peripheral Driver Interface / GPIO.

Removes architecture specific includes from documentation of module  Peripheral Driver Interface / GPIO.

net/nanocoap: make data pointer c++ compliant

cpu/atmega*: factorise common code into atmega_common

The unification of a bigger stack for the atmega platforms
makes some boards to not have enough memory to provide
the big stack plus the application code.

It is possible though, to override the stack size to a
smaller amount if running the test is necessary.

This variable helps to inform at boot time that some
information about the booting process, e.g. reset cause.

Empty array uint8_t data[] is not allowed in ISO-C++. Replacement: function coap_hdr_data_ptr, which handles
the pointer arithmetic to point where hdr.data pointed

The `atmega_set_prescaler` was using a "sensible" default
but it's better to define it at the board level to make
it clear.

This adds a LED_PANIC macro which defines which LED,
or combination of LEDs should notify a panic error.
This is currently used to signal BADISR_vect errors.

cpu.c and startup.c were redundant in most platforms, except for
atmega256rfr2. The common code is now in cpu/atmega_common/cpu.c
and cpu/atmega_common/startup.c. cpu_conf.h is also removed as
it's now in cpu/atmega_common/include thus shared by all atmega
based platforms.

Removes redundancy of code since all the boards were defining
the same variables. Moreover, the stack sizes are unified per
architecture, as required.

Removes duplicated code for atmega platforms. They were all
basically the same, only with the exception of atmegarfr2,
for which there is an #if statement to use the code in the
same file.

xtimer: timer & target overflow, hang resolved.

openocd.sh: fix binfile on osx

sys/auto_init: Fixed initialization of sht1x

example/nanocoap: fix block2 payload

1. When the 32 bit target of the xtimer overflowed the timer was not placed in the right list.
2. When the hardware timer overflowed the comparison was wrong for setting next target.

3. Backoff condition

cpu/esp32: allow explicit ESP32 crystal freq configuration

test/xtimer_hang: DEBUG_PINS