On some systems, <syslog.h> defines syslog to another symbol, so that

syslog.lo does not contain the expected symbols. Including <symbol.h>
in basic_functions.c fixes the resulting linking problem.

ext/standard/basic_functions.c

@@ -44,6 +44,9 @@
 #if HAVE_LOCALE_H
 #include <locale.h>
 #endif
+#ifndef PHP_WIN32
+#include <syslog.h>		/* for possible syslog macro */
+#endif
 #include "safe_mode.h"
 #ifdef PHP_WIN32
 #include "win32/unistd.h"