It seems gcc is not producing debug information for sections which
are not properly marked as "ax", resulting in missing debug info
for _vector_table, _interrupt_handler and _panic_handler. This can be
verified e.g. with
readelf --debug=info ./build/esp-idf/riscv/CMakeFiles/__idf_riscv.dir/vectors.S.obj
readelf -SW ./build/esp-idf/riscv/CMakeFiles/__idf_riscv.dir/vectors.S.obj
for hello_world example on esp32c3 target. Mark the .exception_vectors.text and
.exception_vectors_table.text sections as writable and allocatable so the debug
info sections are generated.
Signed-off-by: Frantisek Hrbata <frantisek.hrbata@espressif.com>