remains from glod

remove unused variable

Purge LLGLSLShader::sNoFixedFunction, and all that flows from it. No functional changes.

Approved-by: Michael Pohoreski
Approved-by: Dave Parks

Introduce LLAppViewer::onCleanup(), a method that accepts a nullary callable
to execute once viewer shutdown begins. Fire the collected callables in
LLAppViewer::cleanup().

In llstartup.cpp, instead of declaring a static unique_ptr and relying on
static object destruction to clean up the "General" ThreadPool, bind the
pointer to the new ThreadPool into an onCleanup() lambda that will delete it
when called. ~ThreadPool() takes care of orderly shutdown.

Use hard tabs because most of the existing function uses those.

Use hard tabs as most of the class declaration already uses those.

Turns out that one of our WorkQueue integration tests was relying on the
incorrect runFor() behavior that we just fixed, so the test broke. Now that
runFor() doesn't wait around for work to be posted, use an explicit wait loop
instead.

To support this, add LLCond::get(functor), where functor must accept a const
reference to the stored data. This new get() returns whatever the functor
returns, allowing a caller to peek at the stored data.

Also use universal references for all remaining LLCond functor arguments.

Reverting a merge is sticky: it tells git you never want to see that branch
again. Merging the DRTVWR-546 branch, which contained the revert, into the
glthread branch undid much of the development work on that branch. To restore
it we must revert the revert.

This reverts commit 029b41c0.

runFor(interval) and runUntil(timestamp) are intended, and documented, to run
*no longer than* the specified time. Instead, the initial implementation
always waited the full specified time, hoping for work to arrive. Fix that:
once we clear work that's already pending, return right away.

It can happen that we try to post() work for LLWindowWin32's window thread
after the thread's WorkQueue has been closed.

Also, instead of giving the "General" ThreadPool static lifespan, put it on
the heap, anchored with a static unique_ptr.

It's sometimes important to finish other initialization before launching the
threads in the ThreadPool, so make that an explicit step. In particular, we
were launching the LLImageGL texture thread before initializing the GL
context, resulting in all gray textures.

SL-16239 Fix for slowdown on AMD GPUs (disable core profile and remove volatile members from LLVertexBuffer)

Add LLWindowWin32Thread::Post(), like post() except it uses PostMessage() to
send the work item to the window thread. Support this in mainWindowProc().

Move LLWindowWin32::recreateWindow()'s destroy_window_handler() call onto the
window thread. Delaying destruction of the old HWND ensures that we can use
PostMessage() and GetMessage() with that HWND to pass the lambda work item.
Moreover, it's likely to be less buggy to call DestroyWindow() on the same
thread that created the window.

Make recreateWindow()'s window thread lambda bind the window class parameters
by value, rather than binding 'this' and back-referencing LLWindowWin32
members.

Make recreateWindow() construct the window thread lambda and then decide
whether to pass it to the window thread using post() or Post(), depending on
whether we have a current HWND -- therefore whether the window thread is
blocked on GetMessage(). That means we can eliminate the kickWindowThread()
call.

Make destroy_window_handler() accept HWND by value rather than by non-const
reference. Since it doesn't attempt to modify the caller's value, this is a
better match for the function's semantics anyway -- but importantly, it lets
us pass a const HWND.

and correspondingly, ll_convert<std::wstring>(const wchar_t*).

Now that we're using ll_convert() for single-argument stringize(arg), make
sure it can efficiently handle the simple case of constructing a string from a
const char pointer.