Added error message if browscap location is not set in php.ini

ext/standard/browscap.c

@@ -220,6 +220,7 @@ PHP_FUNCTION(get_browser)
 	char *lookup_browser_name;
 
 	if (!INI_STR("browscap")) {
+		php_error_docref(NULL TSRMLS_CC, E_WARNING, "browscap ini directive not set.");
 		RETURN_FALSE;
 	}