In plugin-runner, do scandirat() or scandir() instead of readdir().
* plugin-runner.c (set_cloexec_flag): Only define if O_CLOEXEC is not defined, it is not called otherwise. (main): Remove variables "dir" and "dirst"; new variable "dir_fd". Use scandirat() if available, scandir() otherwise, both using new filter function "good_name". Removed checking of plugin file name patterns; this is now done by "good_name". Do not set FD_CLOEXEC flag on plugin_fd, since fexecve() will not work with it. Use pipe2() to set O_CLOEXEC on pipe FD's (if possible). (main/good_name): New filter function for scandirat() or scandir().