* Move ICACHE_* to unique sections, local LD script
Similar to PROGMEM changes, make the name of each ICACHE_* variable/fuction
unique to avoid issues with section conflicts.
Also rename the generated LD linker script to avoid issue with older copies
of the eagle.app.v6.common.ld which were generated by the build process
in a global directory before being moved to the {build.path}. The linker
would use the older, generated *.ld file instead of the generated one, which
would lead to runtime failures on some systems and cause the VTABLE location
to not correspond to the IDE menu selection.
Fixes#5115, and is an update to #5117 and #5116.
* Update boards.txt.py and platform.io build
boards generator updates:
* simplified mapping description: only flash and spiffs sizes are needed
* some ldscripts are renamed due to autogenerated names
* +2M/0, +2M/512K spiffs, +4M0
* reduce length of hidden strings in boards.txt (#5100, https://github.com/arduino/arduino-builder/issues/284)
* give more details in ldscripts (address, size, +rf-cal, +sdk-wifi-settings)
arduino-builder 1.3.25 (shipped with Arduino 1.8.5) forces full
recompilation when any file in the core directory is modified. Avoid
full recompilation by placing generated ld script into build
directory, not source directory.
Also fix an issue where git version description would not be generated
if there were spaces in build path.
