I believe that likely's are needed in __uClibc_main.c for these. Fixed unnecessary including of routines in my case. (ELF, but can not do weak_function *sigh*.) ... /* Arrange for dtors to run at exit. */ if (likely((int)_fini) && likely((int)atexit)) { atexit (&_fini); } /* Run all ctors now. */ if (likely((int)_init)) _init(); ...