cmake: enable linker warnings on common symbols
cmake: enable linker warnings on common symbols

GCC since version 10 uses -fno-common by default and will not emit
common symbols. Enable this option to find the occurrences of common
symbols in ESP-IDF.

Closes https://github.com/espressif/esp-idf/issues/5080

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf