Locating and checking the length of the `ARM_LIB_HEAP` region is an
extra task, when we're just interested in the base and limit. Looking at
only those saves 8 bytes of ROM.
More space could be saved if we ensured all targets had `ARM_LIB_HEAP`,
removing the need for this run-time fallback code.
When moving to the second heap region due to overflowing the first
region, the `_sbrk` implementation assumed the allocation would fit in
the second region, and didn't check for that overflowing too.
Problem revealed in `stats_heap` test with GCC 8 on K64F - the allocation
attempt for 1GiB crashed, as `_sbrk` indicated 1GiB was available at the
start of the second region.
second region.
Presumably older versions of newlib fault that allocation attempt before
passing to `_sbrk`.
While there, adjust the code to not use a separate static `bool`, saving
RAM. We can track with just one pointer, as order of the two regions is
fixed, and already relied on by newlib.
The ARMC6 compiler inadvertently introduces the `_scanf_mbtowc` symbol
to the build. The commit provides a weak definition of the symbol to
satisfy the linker whenever the symbol is included. This affects ARM
Compiler 6 version 6.12 and earlier.
The compiler error was previously observed when the MICROLIB library is
used with the uARM toolchain. However, the weak definition was put in
`mbed-os/rtos` which is not included when the bare metal profile is used.
Also includes:
* rename `mbed_sleep_manager.c` to `mbed_power_mgmt.c` to match its
header file
* create Doxygen groups for public and internal APIs
* use relative path to include header files where inconsistent
* update references to internal APIs throughout libraries
* update the copyright year for all modified files