UnixWare defines shutdown to _shutdown, which causes problems later

on when using a structure member named shutdown. Since this source
file does not use the system call shutdown, it is safe to #undef it.

PR: #6008, #6362

sapi/apache/mod_php4.c

@@ -63,6 +63,8 @@
 # include "mod_dav.h"
 #endif
 
+#undef shutdown
+
 int apache_php_module_main(request_rec *r, int display_source_mode CLS_DC ELS_DC PLS_DC SLS_DC);
 void php_save_umask(void);
 void php_restore_umask(void);