Linker script generator produces build/esp32/esp32.common.ld from
components/esp32/ld/esp32.common.ld.in
This works fine until IDF is downgraded to V3.1 which uses components/esp32/ld/esp32.common.ld and
doesn't track build/esp32/esp32.common.ld at all.
At this point, the linker runs in the build/esp32 directory and "-T esp32.common.ld" picks up the
linker script generated .ld file, which causes mis-builds.
As reported on forums: https://esp32.com/viewtopic.php?f=13&t=9684&p=40105
Added a new structure esp_app_desc_t. It has info about firmware:
version, secure_version, project_name, time/date build and IDF version.
Added the ability to add a custom structure with a description of the firmware.
The esp_app_desc_t is located in fixed place in start of ROM secotor. It is located after structures esp_image_header_t and esp_image_segment_header_t.
app_version is filed from PROJECT_VER variable (if set in custom make file) or PROJECT_PATH/version.txt or git repo (git describe).
Add API to get app_desc from partition.