tiobench: fix aligned allocation method clash with newer glibc

glibc 2.16 added aligned allocation support to stdlib and those
function clashes with the local implementation done in tiobench. We
fix it using a '_' prefix on those.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>