made marker file lock use append, not truncate

more fixes for unit test crashes
added llcommon initialization/teardown for unit tests
that indirectly trigger lltrace
changed access of atomic refcount to use preincrement/decrement
operators to reflect desired semantics
always call apr_initialize in LLCommon::initClass, even
if already initialized...apr does internal reference counting
to keep things straight

fix for unit test failures...cleanup apr without destroying
pools, allowing LLProxy to clean itself up as a singleton (and
avoiding spurious dependencies associated with manually destorying
singletons that rely on apr pools)

fixed crash on exit by making LLInstanceTracker iterators use atomic iterator
nesting count for thread safety

improvements on lifetime of lltrace core data structures
tweaks to thread local pointer handling so that static constructors/destructors
can safely call functions that use lltrace

removed some potential data races
got memory stats recording in trace system

eliminated min and max macros from windows.h
got rest of viewer to compile against llfasttimer changes

cleaning up build
moved most includes of windows.h to llwin32headers.h to disable min/max macros, etc
streamlined Time class and consolidated functionality in BlockTimer class
llfasttimer is no longer included via llstring.h, so had to add it manually in several places

fixed trace data gathering and routing from background thread
simplified slave->master thread communication (eliminated redundant recording and proxy object)
improved performance of fast timer data gathering (slow iterators)

renamed LLTrace::ThreadTrace to LLTrace::ThreadRecorder
renamed LLTrace::Sampler to LLTrace::Recording

cleaned up API
samplers are now value types with copy-on-write buffers under the hood
removed coupling with LLThread

factored out lltrace::sampler into separate file
added rudimentary lltrace support to llstatgraph
made llstatgraph use param blocks more effectively
moves initial set of stats over to lltrace
removed windows.h #defines for min and max

fixed various issues related to unit tests and LLThreadLocalPtr initialization and teardown

moved LLThreadLocalPtr to llapr
fixed various startup race conditions for LLThreadLocalPtr

Beware of bad documentation.  operator--(int) does not return what
the header claimed it did.

another attempt at fixing gcc builds

accessed through the static LLThread::tldata().
Currently this object contains two (public) thread-local
objects: a LLAPRRootPool and a LLVolatileAPRPool.

The first is the general memory pool used by this thread
(and this thread alone), while the second is intended
for short lived memory allocations (needed for APR).
The advantages of not mixing those two is that the latter
is used most frequently, and as a result of it's nature
can be destroyed and reconstructed on a "regular" basis.

This patch adds LLAPRPool (completely replacing the old one),
which is a wrapper around apr_pool_t* and has complete
thread-safity checking.

Whenever an apr call requires memory for some resource,
a memory pool in the form of an LLAPRPool object can
be created with the same life-time as this resource;
assuring clean up of the memory no sooner, but also
not much later than the life-time of the resource
that needs the memory.

Many, many function calls and constructors had the
pool parameter simply removed (it is no longer the
concern of the developer, if you don't write code
that actually does an libapr call then you are no
longer bothered with memory pools at all).

However, I kept the notion of short-lived and
long-lived allocations alive (see my remark in
the jira here: https://jira.secondlife.com/browse/STORM-864?focusedCommentId=235356&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-235356
which requires that the LLAPRFile API needs
to allow the user to specify how long they
think a file will stay open. By choosing
'short_lived' as default for the constructor
that immediately opens a file, the number of
instances where this needs to be specified is
drastically reduced however (obviously, any
automatic LLAPRFile is short lived).

***

Addressed Boroondas remarks in https://codereview.secondlife.com/r/99/
regarding (doxygen) comments. This patch effectively only changes comments.

Includes some 'merge' stuff that ended up in llvocache.cpp
(while starting as a bug fix, now only resulting in a cleanup).

***

Added comment 'The use of apr_pool_t is OK here'.

Added this comment on every line where apr_pool_t
is correctly being used.

This should make it easier to spot (future) errors
where someone started to use apr_pool_t; you can
just grep all sources for 'apr_pool_t' and immediately
see where it's being used while LLAPRPool should
have been used.

Note that merging this patch is very easy:
If there are no other uses of apr_pool_t in the code
(one grep) and it compiles, then it will work.

***

Second Merge (needed to remove 'delete mCreationMutex'
from LLImageDecodeThread::~LLImageDecodeThread).

***

Added back #include <apr_pools.h>.

Apparently that is needed on libapr version 1.2.8.,
the version used by Linden Lab, for calls to
apr_queue_*. This is a bug in libapr (we also
include <apr_queue.h>, that is fixed in (at least) 1.3.7.

Note that 1.2.8 is VERY old. Even 1.3.x is old.

***

License fixes (GPL -> LGPL). And typo in comments.
Addresses merov's comments on the review board.

***

Added Merov's compile fixes for windows.

In addition to its usual apr_sterror() function, APR defines a special
function specifically for errors relating to the apr_dso_*() functions.
Introduce ll_apr_warn_status() and ll_apr_assert_status() overloads accepting
apr_dso_handle_t* to call apr_dso_error() as well as apr_strerror() and log
its output. Use new ll_apr_warn_status() in LLAppViewer::loadEventHostModule()
for apr_dso_load() and apr_dso_sym() calls. Instead of shorthand
ll_apr_assert_status(), use with llassert_always() so check is still performed
even in Release build.
Add more lleventhost-related debugging output, e.g. full pathname of the DLL.
On Mac and Linux, call 'file' command to report nature of the DLL too.

from the end'.
Also, more comments.
Also, try to avoid a seek when offset==0 in read.
To be reviewed by Bao.
(transplanted from 60eb013221a83ff76054ab7dcb1d07c108f51a9d)

some clean-up of lllfsthread to help me understand it, remove one extraneous close().  to be reviewed by bao.
(transplanted from 17c6af7a2396f9890aab8226356a556b4d58a7d8)

and reduce unnecessary dependencies and incredibuild wedging.  Hopefully in
the long run this will reduce build time.  Also cleaned up a lot of header
file usage to conform better to the coding standard.

reviewed by james and steve.

Moves libllcommon.so to a staging dir for unit tests to work
and gets rid of LL_COMMON_API in forward declarations

Ok, finally got this to a point where it doesn't break the build and I can check
in. llcommon can be built as a shared library (disabled but can be enabled with
cmake cache var LLCOMMON_LINK_SHARED.

reviewed by Mani on tuesday (I still need to get his suggested changes
re-reviewed)

svn+ssh://svn.lindenlab.com/svn/linden/branches/viewer/viewer-1.23.onetwo-merge-1

QAR-1531 viewer 1.23rc1+1.23rc2 merge to trunk