[boost] [pool] patch to make pool support zero sized allocations.

Subject: [boost] [pool] patch to make pool support zero sized allocations.
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2009-08-22 15:15:52

AMDG

The patch at
https://svn.boost.org/trac/boost/attachment/ticket/386/pool.patch
allows the pool classes to support zero sized allocation, by returning
a null pointer.  std::vector sometimes allocates a zero sized block,
so this is necessary for pool_allocator.  Returning a null pointer
is the simplest solution and I'm that the standard allows an allocator
to return the null pointer when asked for a block of zero elements.

Okay to commit?

In Christ,
Steven Watanabe