Add define for instrumentation code

src/civetweb.c

@@ -188,7 +188,7 @@ static void DEBUG_TRACE_FUNC(const char *func,
 #endif
 
 
-#if defined(__GNUC__) && defined(DEBUG)
+#if defined(__GNUC__) && defined(GCC_INSTRUMENTATION)
 void __cyg_profile_func_enter(void *this_fn, void *call_site)
     __attribute__((no_instrument_function));