postfix-3.6.2 compilation fails with glibc-2.34

[Jaroslav Skarvada]

Hi,

glibc-2.34 introduced the closefrom function which causes postfix build to fail:

In file included from ./vstream.h:22,
                 from attr_print64.c:100:
/usr/include/unistd.h:363:13: error: conflicting types for 'closefrom'; have 'vo
  363 | extern void closefrom (int __lowfd) __THROW;
      |             ^~~~~~~~~
In file included from attr_print64.c:92:
./sys_defs.h:1512:12: note: previous declaration of 'closefrom' with type 'int(i
 1512 | extern int closefrom(int);
      |            ^~~~~~~~~

I think the def in the header src/util/sys_defs.h needs to be adjusted
accordingly

thanks & regards

Jaroslav