Revert "nss: prevent PROTECT_ERRNO from squashing changes to *errnop"

This reverts commit b26c904113.

I don't see anythign wrong, but Ubuntu autopkgtest CI started failing fairly
consistently since this was merged. Let's see if reverting fixes things.

src/test/test-fs-util.c

@@ -361,11 +361,11 @@ static void test_unlink_noerrno(void) {
 
         {
                 PROTECT_ERRNO;
-                errno = 42;
+                errno = -42;
                 assert_se(unlink_noerrno(name) >= 0);
-                assert_se(errno == 42);
+                assert_se(errno == -42);
                 assert_se(unlink_noerrno(name) < 0);
-                assert_se(errno == 42);
+                assert_se(errno == -42);
         }
 }
 

src/test/test-util.c

@@ -213,70 +213,6 @@ static void test_protect_errno(void) {
         assert_se(errno == 12);
 }
 
-static void test_protect_errno_disarmed(void) {
-        log_info("/* %s */", __func__);
-
-        errno = 12;
-        /**
-         * Simulate dynamically-linked glibc calling the NSS module with errnop
-         * and &errno being the same.
-         */
-        int *errnop = &errno;
-
-        {
-                PROTECT_ERRNO;
-
-                *errnop = DISARM_PROTECT_ERRNO(25);
-        }
-
-        assert_se(errno == 25);
-        assert_se(*errnop == 25);
-}
-
-static void test_protect_errno_disarmed_inner(void) {
-        log_info("/* %s */", __func__);
-
-        errno = 12;
-        int *errnop = &errno;
-
-        {
-                PROTECT_ERRNO;
-
-                int *_saved_errno_p = &_saved_errno_;
-                *errnop = DISARM_PROTECT_ERRNO_INNER(25);
-        }
-
-        assert_se(errno == 25);
-        assert_se(*errnop == 25);
-}
-
-static void test_protect_errno_disarmed_static(void) {
-        log_info("/* %s */", __func__);
-
-        errno = 12;
-        /*
-         * "In statically linked programs, the main application and NSS
-         * modules do not share the same thread-local variable errno,
-         * which is the reason why there is an explicit errnop function
-         * argument."
-         */
-        int errno2 = 15;
-        int *errnop = &errno2;
-
-        {
-                PROTECT_ERRNO;
-
-                errno = 13;
-                *errnop = DISARM_PROTECT_ERRNO(25);
-                assert_se(errno == 12);
-
-                errno = 14;
-        }
-
-        assert_se(errno == 14);
-        assert_se(*errnop == 25);
-}
-
 static void test_in_set(void) {
         log_info("/* %s */", __func__);
 
@@ -447,9 +383,6 @@ int main(int argc, char *argv[]) {
         test_div_round_up();
         test_u64log2();
         test_protect_errno();
-        test_protect_errno_disarmed();
-        test_protect_errno_disarmed_inner();
-        test_protect_errno_disarmed_static();
         test_in_set();
         test_log2i();
         test_eqzero();