Deriving your tracked class T from LLInstanceTracker<T> gives you
T::getInstance() et al. But what about a subclass S derived from T?
S::getInstance() still delivers a pointer to T, requiring explicit downcast.
And so on for other LLInstanceTracker methods.

Instead, derive S from LLInstanceTrackerSubclass<S, T>. This implies that S is
a grandchild class of T, but it also recasts the LLInstanceTracker methods to
deliver results for S rather than for T.

SL-18154 Profile guided optimizations vs release viewer.  Trim some unused abilities and remove some more fast timers.

This still needs some work - I'm not super satisfied with the overall structure of the code.  Will continue to iterate as I add in proper RenderDoc support.

SL-18239 Unify PBR and non-PBR treatment of ambient/SSAO/irradiance.  Restore SSAO to release version.

SL-18078, SL-18065 -- Experimentally allow uploading of lossless normal maps, fix for crash on shutdown.

SL-17485-b - Attempt to make teamcity builds happy by not referencing a newview global from an llcommon file.

The work queue callback binds "this". This is deemed safe due to current dependencies, but see the associated comment in the return callback. There was some trial and error to get a this-binded lambda to compile.

Due to LLVorbisDecodeState writing to disk off-thread, limit audio decodes proportional to general worker thread count. Guess the thread count for now.

(cherry picked from commit 41d6a0e222241606c317281e2f0b211e16813dd5)

SL-17485 - Provide corrected missing memory data on mac: sAllocatedPageSizeInKB, sAllocatedMemInKB, sAvailPhysicalMemInKB, sMaxPhysicalMemInKB

and for LLViewerControlListener, to which it talks.

Fix glitches detected by the tests.

Log ThreadPoolSizes at DEBUG level, not INFO.

Introduce CommonControl, which in a running viewer (or any program containing
an LLViewerControlListener instance) gives access to LLViewerControl
functionality, e.g. getting, setting or enumerating control variables --
without introducing a link dependency on newview.

Make ThreadPool's constructor consult CommonControl to check for an override
for the width of the new ThreadPool in the Global (i.e. gSavedSettings)
setting ThreadPoolSizes, and honor that if found.

Introduce static ThreadPool methods getConfiguredWidth(), to query for such an
override on any particular ThreadPool name; and getWidth(), to ask for the
width of an instance if that instance already exists, else the width with
which it *would* be instantiated.

(cherry picked from commit 41d6a0e222241606c317281e2f0b211e16813dd5)

We inadvertently changed tryPost() to call ThreadSafeSchedule::tryPost(),
which doesn't exist.

SL-17077 Ensure profiling is disabled if gpu_benchmark fails.  Log the source of the real crash for when the viewer inevitably crashes later.

SL-16815 and SL-16906 Avoid redundant bumpmap generation, add some assertions around ref counting and (hack) fix crash on shutdown from dangling texture reference (reduced to 1 dangling texture from several hundred, can't find the remaining reference).

SL-14961 works better for windows than rethrow

Rename 'winlevel()' to 'sehandle()'; change it from a static member function
to a free function, thus eliminating the conditional in llcoros.h.

Elsewhere than Windows, provide a zero-cost pass-through sehandle()
implementation, eliminating the conditional in toplevel().

# Conflicts:
#	indra/llcommon/llcoros.cpp
#	indra/llcommon/llcoros.h

This mechanism uses a queue of std::exception_ptrs to transport an (otherwise)
uncaught exception from a terminated coroutine to the thread's main fiber. The
main loop calls LLCoros::rethrow() just after giving some cycles to ready
coroutines that frame.

# Conflicts:
#	indra/llcommon/llcoros.cpp
#	indra/llcommon/llcoros.h
#	indra/newview/llappviewer.cpp

Will be replaced with retrow from nat