Currently the SPI driver in core/ sets `SPI_FLUSH()` to be a single read
of the spi RX buffer. This is fine for many microcontrollers, but newer
platforms like the CC2538 have a multi-byte FIFO for the RX buffer. In
that case, a single read is not guaranteed to flush the RX. This commit
allows `SPI_FLUSH()` to be platform dependent if needed, but doesn't
change for platforms where it works.
char is signed but uip_buf is unsigned
spi.h:
casted unused values to void
autostart.c:
autostart.h:
The array itself should be const but the processes pointed to
should not.
profile-aggregates.c:
sizeof returns unsigned long on my platform
