Add valgrind support

Teach valgrind about apr pools, allocators, and bucket allocators
if --with-valgrind is passed to configure.

This has less impact on program behavior and performance than compiling
with complete pool-debugging. Even with valgrind support compiled in,
the performance impact if not running under valgrind should be minimal. 

It may make sense to use pool-debugging together with valgrind support
because pool-debugging does not help with allocators and bucket
allocators.



git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1438957 13f79535-47bb-0310-9956-ffa450edef68
Only fill in apr_sockaddr_vars_set if we have valid data


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1438958 13f79535-47bb-0310-9956-ffa450edef68