add ltc_mp_digit to sizes and tests

src/misc/crypt/crypt_sizes.c

@@ -273,6 +273,7 @@ static const crypt_size _crypt_sizes[] = {
     _SZ_STRINGIFY_T(crc32_state),
 #endif
 
+    _SZ_STRINGIFY_T(ltc_mp_digit),
     _SZ_STRINGIFY_T(ltc_math_descriptor)
 
 };

tests/test.c

@@ -331,6 +331,7 @@ int main(int argc, char **argv)
    printf("NO math provider selected, all tests requiring MPI were disabled and will 'nop'\n");
 #endif
 
+   printf("sizeof(ltc_mp_digit) = %d\n", (int)sizeof(ltc_mp_digit));
 
 #ifdef LTC_PTHREAD
    tinfo = XCALLOC(sizeof(test_functions)/sizeof(test_functions[0]), sizeof(thread_info));