posix_memalign() is allowed to return NULL if the size is zero.  toku_xmalloc_aligned has an overactive assertion that complains in this situation, and appears when running ft-test with an implementation that returns NULL.  This patch makes ft-test run to completion with such an implementation.
posix_memalign() is allowed to return NULL if the size is zero.  toku_xmalloc_aligned has an overactive assertion that complains in this situation, and appears when running ft-test with an implementation that returns NULL.  This patch makes ft-test run to completion with such an implementation.

ottok/PerconaFT,ottok/PerconaFT,percona/PerconaFT,kuszmaul/PerconaFT-tmp,kuszmaul/PerconaFT,percona/PerconaFT,kuszmaul/PerconaFT-tmp,BohuTANG/ft-index,percona/PerconaFT,BohuTANG/ft-index,kuszmaul/PerconaFT,kuszmaul/PerconaFT-tmp,kuszmaul/PerconaFT,BohuTANG/ft-index,percona/PerconaFT,kuszmaul/PerconaFT-tmp,ottok/PerconaFT,BohuTANG/ft-index,kuszmaul/PerconaFT,ottok/PerconaFT