[OMPD] The LLVM OMPD library ompd_callbacks_t structure is wrong

[jdelsign]

The "struct ompd_callbacks_t" used by the LLVM OMPD library does not match the OpenMP v5.0 spec (or the OpenMP omp-tools.h header). In particular, it is missing the read_string function pointer, which causes the structure to be the wrong size and the structure members. The definition used by the LLVM OMPD library is here: https://github.com/OpenMPToolsInterface/LLVM-openmp/blob/ompd-devices/libompd/src/ompd.h#L238

The correct definition of struct ompd_callbacks_t (from the OpenMP omp-tools.h header) is:

typedef struct ompd_callbacks_t {
  ompd_callback_memory_alloc_fn_t alloc_memory;
  ompd_callback_memory_free_fn_t free_memory;
  ompd_callback_print_string_fn_t print_string;
  ompd_callback_sizeof_fn_t sizeof_type;
  ompd_callback_symbol_addr_fn_t symbol_addr_lookup;
  ompd_callback_memory_read_fn_t read_memory;
  ompd_callback_memory_write_fn_t write_memory;
  ompd_callback_memory_read_fn_t read_string;
  ompd_callback_device_host_fn_t device_to_host;
  ompd_callback_device_host_fn_t host_to_device;
  ompd_callback_get_thread_context_for_thread_id_fn_t
      get_thread_context_for_thread_id;
} ompd_callbacks_t;