Switching back to __builtin_bswap32.
Switching back to __builtin_bswap32.

BUG=None
TEST=devenv-latest
R=sbc@chromium.org

Review URL: https://codereview.chromium.org/617003014

yeyus/naclports,Schibum/naclports,yeyus/naclports,Schibum/naclports,kuscsik/naclports,dtkav/naclports,yeyus/naclports,yeyus/naclports,dtkav/naclports,kuscsik/naclports,yeyus/naclports,kuscsik/naclports,Schibum/naclports,Schibum/naclports,kuscsik/naclports,yeyus/naclports,Schibum/naclports,kuscsik/naclports,dtkav/naclports,Schibum/naclports,dtkav/naclports,dtkav/naclports