Recent versions of gcc say this:

ltdl.c:2893:34: warning: division 'sizeof (lt_caller_data * {aka struct <anonymous> *}) / sizeof (lt_caller_data {aka struct <anonymous>})' does not compute the number of array elements [-Wsizeof-pointer-div]

Source code is

#define N_ELEMENTS(a)   (sizeof(a) / sizeof(*(a)))

and the call sites are like this:

    n_elements = N_ELEMENTS (handle->caller_data);