* reverted old faulty mechanism to set different
standard according to the toolchain
* Using -std=gnu++2b now for both gcc and clang
* Added a build test app to check the C++ standard in IDF
* Updated english docs to reflect the change to C++23
Changed rv_utils_intr_edge_ack and esp_cpu_intr_edge_ack to
take uint32_t instead of int to avoid build errors.
The test is to test in particular that __builtin_ffsll, used in
xt_utils.h, which is included via esp_cpu.h, compiles fine
in C++20 with -Wsign-conversion enabled.
Closes https://github.com/espressif/esp-idf/pull/10895
In C++20, using the result of an assignment to a 'volatile' value is
deprecated.
Breaking change: register "setter" or modification macros can no
longer be used as expressions.
Closes https://github.com/espressif/esp-idf/issues/9170
