[klibc] klibc warnings

[H. Peter Anvin]

Sam Ravnborg wrote:
> Noticed a few warnings while playing with klibc.
> Would be nice to have them fixed before pushing
> for inclusion in the kernel.
> 
> usr/lib/readdir.c: In function `readdir':
> usr/lib/readdir.c:54: warning: use of cast expressions as lvalues is deprecated
> 
> usr/lib/qsort.c: In function `qsort':
> usr/lib/qsort.c:33: warning: use of cast expressions as lvalues is deprecated

*Sigh* the above is a result of the gcc team trying to kill off a decade-old, 
useful, documented, and heavily utilized extension.  Anyway, I'll fix these.

> usr/lib/sha1hash.c: In function `main':
> usr/lib/sha1hash.c:292: warning: unused variable `j'

	-hpa