ftp.c is the only user of this function so making it static in that file
allows it to be inlined. Also, reusing unichar_toupper means we no longer
depend on the C stdlib for toupper, saving about 300 bytes of code space.
In order to have more fine-grained control over how builtin functions are
constructed, the MP_DECLARE_CONST_FUN_OBJ macros are made more specific,
with suffix of _0, _1, _2, _3, _VAR, _VAR_BETEEN or _KW. These names now
match the MP_DEFINE_CONST_FUN_OBJ macros.
py/mphal.h contains declarations for generic mp_hal_XXX functions, such
as stdio and delay/ticks, which ports should provide definitions for. A
port will also provide mphalport.h with further HAL declarations.
The bootloader needs string0.c because of memset, memcpy and others,
without string0.c it magically links, but calling any of those
functions results in a hard fault.
In debug mode, modpyb needs printf, and including stdio.h leads to
conflicts due to the redefinitions made in the simplelink drivers.
Such functions are never used after MicroPython has started, and they
remain in RAM wasting space. Now they are placed in a special section
named "boot" which sits just before the heap, allowing us to extend
the effective heap area up to the new boot section. Right now, this
gives us back ~1K, but in the future, more functions might end up in
there as well.
The port currently implements support for GPIO, RTC, ExtInt and the WiFi
subsystem. A small file system is available in the serial flash. A
bootloader which makes OTA updates possible, is also part of this initial
implementation.
