test/asn1_time_test.c: Better check of signed time_t

int setup_tests(void)

{

    /*

     * On platforms where |time_t| is an unsigned integer, t will be a

     * positive number.

     *

     * We check if we're on a platform with a signed |time_t| with '!(t > 0)'

     * because some compilers are picky if you do 't < 0', or even 't <= 0'

     * if |t| is unsigned.

     */

    time_t t = -1;

    /*

     * On some platforms, |time_t| is signed, but a negative value is an

     * error, and using it with gmtime() or localtime() generates a NULL.

     * If that is the case, we can't perform tests on negative values.

     */

    struct tm *ptm = localtime(&t);

    ADD_ALL_TESTS(test_table_pos, OSSL_NELEM(tbl_testdata_pos));

    if (ptm != NULL) {

    if (!(t > 0) && ptm != NULL) {

        TEST_info("Adding negative-sign time_t tests");

        ADD_ALL_TESTS(test_table_neg, OSSL_NELEM(tbl_testdata_neg));

    }

    if (sizeof(time_t) > sizeof(uint32_t)) {

        TEST_info("Adding 64-bit time_t tests");

        ADD_ALL_TESTS(test_table_pos_64bit, OSSL_NELEM(tbl_testdata_pos_64bit));

        if (ptm != NULL) {

        if (!(t > 0) && ptm != NULL) {

            TEST_info("Adding negative-sign 64-bit time_t tests");

            ADD_ALL_TESTS(test_table_neg_64bit, OSSL_NELEM(tbl_testdata_neg_64bit));

        }