Provide emulated atomic load & store libcalls for u8, u16 & u32 integer
types. This is required when building with Clang as llvm does not lower
these operations to native load / stores, where as gcc does.
Provide `sync_lock_test_and_set` atomic implementations for all
supported integer types.
Closes https://github.com/espressif/esp-idf/issues/7591.
Closes https://github.com/espressif/esp-idf/issues/7592.