VS 2017 complains about the same thing that clang does: casting S32 to GLvoid*
can't possibly produce a valid pointer value because S32 can't fit a whole
64-bit pointer. To appease it, not only must we use reinterpret_cast, but we
must first cast S32 to intptr_t and then reinterpret_cast THAT.

Fix broken throttling of sky/envmap updates.

Add code to force a usage hint when VBOs are disabled and make useBVOs reflect that as well.

Make shadowAlphaMask shader ignore vertex alpha before discards iff we're a fullbright object.

Keep llappearance from stuffing dangling pointers into the alpha cache (crash iff you're using nSight debugging and disable readbacks).

Code cleanup and move to using typedefs of S64Seconds/F64Seconds for ease in sync w/ sim side which has not llunits types.

Error to help figuring out if error happens due to gl or memory issue

Ruslan points out that changing TYPE_MAX could lead to extra (useless) render
passes. We will have to solve the TYPE_INDEX > TYPE_MAX problem another way.

Ruslan assures me that in fact this usage is valid.

when passing -- something -- to glVertexAttribPointerARB() in
LLVertexBuffer::setupVertexArray().

LLVertexBuffer::TYPE_INDEX was past TYPE_MAX, which is used to set the maximum
sizes of various (scattered) arrays, bleh. The alarm bells that this SHOULD
set off are indeed correct: TYPE_INDEX was being used to index at least one of
those arrays, meaning we've been indexing past the end of that array, meaning
undefined behavior.

The enum that defines both TYPE_INDEX and TYPE_MAX provides a helpful comment
indicating what things must be updated when modifying the enum. (Far better to
define things centrally in a single place... but another time.) Update the
designated arrays to include a final TYPE_INDEX entry. Contents of those
entries are wild guesses -- but even wild guesses are better than completely
indeterminate data.

MAINT-6910 - [MAINT-RC] Some mesh turns invisible when camera is moved on the Maint-RC viewer only - caused by fix for MAINT-6125.

Commulative fix.
Fixed for booth ticket's in indra/newview/llvovolume.cpp
Remained fixed, it's a small code improvements which is not related to
MAINT-6125, MAINT-6910

MAINT-6910 - [MAINT-RC] Some mesh turns invisible when camera is moved on the Maint-RC viewer only - caused by fix for MAINT-6125.

Commulative fix.
Fixed for booth ticket's in indra/newview/llvovolume.cpp
Remained fixed, it's a small code improvements which is not related to
MAINT-6125, MAINT-6910