[PATCH] memset: fix define usage for shared libs

[David Miller]

From: Mike Frysinger <vapier@gentoo.org>
Date: Wed,  4 Apr 2012 21:26:02 -0400

> The proper define to check "am I in a shared lib" is "SHARED", not "PIC".
> The two new memset_chk functions incorrectly depend on "PIC".

I'm ambivalent on this one, because there are other locations
where we essentially test libc.a vs. libc.so using PIC too.