asprintf.c: use long double type for calculation 2^32 - 1

c-programming/strings/asprintf.c

@@ -60,7 +60,7 @@ int main(void) {
 	ssize_t result = asprintf(&output, "Hello%s! -- Unsigned 32-bit type is "
 		"constrained to lie\nwithin the range of integer values from "
 		"%" PRIu32 " to %" PRIu32 " inclusive.", world, 0,
-		(uint32_t) (powf(2.0f, 32.0f) - 1.0f));
+		(uint32_t) (powl(2.0L, 32.0L) - 1.0L));
 
 	PRINT_ASSERT("no segmentation fault", true);
 	PRINT_ASSERT("no errors occurred", result != -1);