SharedForward: Hard-code the ldpath buffer size to below VS 14 limit

Visual Studio 14 (2015) complains if a static character array is
declared with more than 65535 elements.  This limit should be large
enough for SharedForward clients, so just hard-code that instead of
trying to compute a limit.

Change-Id: Ib24195b0d0972bdabaf5a18b93a1a9b8c43dc773