be more specific as to what arguments to __uClibc_main() people can skim on during initial port

docs/PORTING

@@ -27,7 +27,7 @@ you are hacking on.
   the funcion __uClibc_main() which takes these parameters:
    __uClibc_main(main(), argc, argv, _init(), _fini())
   Initially if you wish to make things easier on yourself, you can disable the
-  UCLIBC_CTOR_DTOR option and just set those two arguments to NULL
+  UCLIBC_CTOR_DTOR option and just set the init/fini arguments to NULL.
   glibc generally stores this function in libc/sysdeps/ARCH/elf/start.S
 
 - create these additional files in ARCH/bits/