[PATCH] -Duselargefiles for VMS

The CRTL infrastructure to do this been available for a year or two or
three but I've just now gotten around to configuring for it. It got a
bit more interesting than I expected, mainly because we have a custom
stat structure that overlays the CRTL stat structure, and the latter is
a completely different beast when _LARGEFILE is defined. The attached
patch does not introduce any test failures, though I assume the test
suite is not actually creating files over 2GB in size. Does anyone have
some good large file tests?

There are also some cosmetic changes here to configure.com for other
64-bit items, but there is more to do in this arena. For example,
-Duse64bitall does not actually enable 64-bit pointers even though long
pointers have been available on Alpha for 6 or 8 years now.

• [PATCH] -Duselargefiles for VMS by Craig A. Berry