Complimentary changes:
1) Partition table definitions files with core dump partition
2) Special sub-type for core dump partition
3) Special version of spi_flash_xxx
4) espcoredump.py is script to get core dump from flash and print useful info
5) FreeRTOS API was extended to get tasks snapshots
On Xtensa windowed ABI backtrace is easy to do, and it's immensely
useful for debugging, so - do it by default.
We try to be careful and not deref bogus pointers while walking the
frames.
Example output (from debugging espressif/esp-idf#133):
Backtrace: 0x1:0x3ffc51e0 0x400e9dfa:0x3ffc5210 0x400e9ebc:0x3ffc5230 0x400ec487:0x3ffc5260
With just addr2line utility from binutils, this already pinpoints the
location of the crash.