Fails to build with GCC 13

[marxin]

Fails due to the following header changes:
https://gcc.gnu.org/gcc-13/porting_to.html#header-dep-changes

$ osc co openSUSE:Factory/yast2-core
$ cd $_
$ osc build --alternative-project devel:gcc:next
...
[   26s] y2changes.cc: In function 'std::string y2_changesfmt_prefix(logcategory_t)':
[   26s] y2changes.cc:135:24: error: 'time' was not declared in this scope; did you mean 'utimes'?
[   26s]   135 |     time_t timestamp = time (NULL);
[   26s]       |                        ^~~~
[   26s]       |                        utimes
[   26s] y2changes.cc:136:29: error: 'localtime' was not declared in this scope
[   26s]   136 |     struct tm *brokentime = localtime (&timestamp);
[   26s]       |                             ^~~~~~~~~
[   26s] y2changes.cc:138:5: error: 'strftime' was not declared in this scope; did you mean 'st_ctime'?
[   26s]   138 |     strftime (date, sizeof (date), Y2CHANGES_DATE, brokentime);
[   26s]       |     ^~~~~~~~
[   26s]       |     st_ctime
[   26s] make[4]: *** [Makefile:569: y2changes.lo] Error 1