ao.m4 hardcodes libdir=lib.
Fixed with libao-1.1.0-r1.ebuild: 20 Aug 2011; Matt Turner <mattst88@gentoo.org> libao-1.0.0-r1.ebuild, libao-1.1.0.ebuild, +libao-1.1.0-r1.ebuild: Fix hardcoded 'lib' in ao.m4. Drop ~mips keywords from older versions.