SERVER-7404 Link to posix_fadvise at runtime for Solaris

For the Solaris/SmartOS build, do not make direct calls to posix_fadvise,
which is present in Solaris 11 but not in Solaris 10.  Instead, see if
it is available in a loaded library (which will be libc.so.1) at runtime
and either call it or call an emulation.  The emulation is a no-op.
SERVER-7404 Visual Studio -- add posix_fadvise.{cpp,h}
SERVER-9976 buildbot metadata_loader_test debug make sure we test optional fields
SERVER-7080 Link to backtrace, backtrace_symbols and backtrace_symbols_fd at runtime

Do not make direct calls to backtrace, backtrace_symbols or backtrace_symbols_fd,
which are present in Solaris 11 but not in Solaris 10.  Instead, see if they are
available in a loaded library (which will be libc.so.1) at runtime and either
call them or call an emulation.
SERVER-7174: remove unreachable return
SERVER-6246 Validate that createUser and updateUser commands don't receive any unexpected arguments
SERVER-6246 Make createUser generate _id for user object
SERVER-6246 Make sure we release the write lock before calling GLE in user management commands
SERVER-6101 Remove no longer necessary try-catch from test
SERVER-6246 Fix indentation of updateUser command
SERVER-7080 Visual Studio -- add backtrace.{cpp,h}
SERVER-6246 Add otherDBRoles to createUser command
SERVER-6246 Check for existence of "code" field before accessing it when creating a user doc
SERVER-9147 unify readahead on all platforms
SERVER-6246 Fix some tests to work with new createUser command
SERVER-6246 Don't query for existing users in addUser shell helper
SERVER-9853 avoid Windows test shutdown issues by stopping the test explicitly