Refactor utsname.domainname struct member Autoconf check

UPGRADING.INTERNALS

@@ -50,6 +50,7 @@ PHP 8.4 INTERNALS UPGRADE NOTES
    - The configure option --with-zlib-dir has been removed.
    - COOKIE_IO_FUNCTIONS_T symbol has been removed (use cookie_io_functions_t).
    - HAVE_SOCKADDR_UN_SUN_LEN symbol renamed to HAVE_STRUCT_SOCKADDR_UN_SUN_LEN.
+   - HAVE_UTSNAME_DOMAINNAME symbol renamed to HAVE_STRUCT_UTSNAME_DOMAINNAME.
    - PHP_CHECK_IN_ADDR_T M4 macro and 'in_addr_t' fallback definition to 'u_int'
      removed (use AC_CHECK_TYPES Autoconf macro instead).
    - HAVE_ODBC2 symbol has been removed in ext/odbc.

ext/posix/config.m4

@@ -36,21 +36,10 @@ int main(int argc, char *argv[])
     AC_MSG_RESULT([no, cannot detect working ttyname_r() when cross compiling. posix_ttyname() will be thread-unsafe])
   ])
 
-  AC_CACHE_CHECK([for utsname.domainname], ac_cv_have_utsname_domainname, [
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-      #ifndef _GNU_SOURCE
-      #define _GNU_SOURCE
-      #endif
-      #include <sys/utsname.h>
-    ]],[[
-      return sizeof(((struct utsname *)0)->domainname);
-    ]])],[
-      ac_cv_have_utsname_domainname=yes
-    ],[
-      ac_cv_have_utsname_domainname=no
-    ])
+  AC_CHECK_MEMBERS([struct utsname.domainname],,,[
+    #ifndef _GNU_SOURCE
+    #define _GNU_SOURCE
+    #endif
+    #include <sys/utsname.h>
   ])
-  if test "$ac_cv_have_utsname_domainname" = yes; then
-    AC_DEFINE(HAVE_UTSNAME_DOMAINNAME, 1, [Whether struct utsname has domainname])
-  fi
 fi

ext/posix/posix.c

@@ -358,7 +358,7 @@ PHP_FUNCTION(posix_uname)
 	add_assoc_string(return_value, "version",  u.version);
 	add_assoc_string(return_value, "machine",  u.machine);
 
-#if defined(_GNU_SOURCE) && !defined(DARWIN) && defined(HAVE_UTSNAME_DOMAINNAME)
+#if defined(_GNU_SOURCE) && defined(HAVE_STRUCT_UTSNAME_DOMAINNAME)
 	add_assoc_string(return_value, "domainname", u.domainname);
 #endif
 }