PATH environment variable is not properly set if using LibraryPath option

The PATH environment variable is not properly set if command line option LibraryPath is used. It shall extend the existing PATH variable with additional directories defined as library path. In the current implementation the wrong buffer size for the retrieved environment variable is passed during the call to GetEnvironmentVariableW from utility function apxAddToPathW (utils.c). Attached a patch that contains the fix for this issue.