Log Message:
Add support for dar-int32 and dar-int64 package options.

Dar is built by default with an arbitrary-size-integer library for managing
all file length/timestamp details.  If 32-bit or 64-bit integers (with
overflow protection) are sufficient for requirements, the dar-int32 and
dar-int64 options can significantly reduce the run-time memory and CPU
overheads of Dar.

Leave the default unchanged (thus no package version bump).