Previously, the following sequence of events was possible:

Background thread                   Main thread
------------------------------------------------------------------------
Lock::tryAcquire()
    Run to blockingMessage->post()

                                    BlockingMessage::messageCallback()
                                        Run to abortWait.set (1)

Lock::tryAcquire()
    Exit through return true

Lock::~Lock()
    Destroy memory used for Lock

                                    BlockingMessage::messageCallback()
                                        Execute lockedEvent.signal()
                                        Memory already freed, crash

In order to display a WebKit based webview a plugin will deploy a
temporary standalone executable on the system and host the WebKit
instance inside that.

This is a breaking change - see BREAKING-CHANGES.txt

Co-authored-by: ValentynPavliuchenkoA <valentyn.pavliuchenko@avid.com>

Following commit 093dbc7df1 pings of a
child process connection need to initialised explicitly. This commit
adds a missing initialisation.

This commit reverts c34f13a02d

In stripped plugin builds, the repostCurrentNSEvent function was still
public. There doesn't seem to be a good reason for this, as no host
should need to call the function.

It looks like the shared code component of a Projucer-generated plugin
project was briefly built as a framework that was shared by the
different plugin wrappers. In this scenario, the framework would need to
make repostCurrentNSEvent public so that the wrappers could locate the
function. However, now that the shared code target is built as a static
library, standard external linkage should be sufficient for the symbol
to be located from the wrapper's TUs.

When the result of find_if() is only compared to the container's end(),
the operation can normally be expressed more concisely using any_of(),
all_of(), or none_of().

This commit removes the various compiler-specific JUCE_DEPRECATED macros and replaces them with C++14's deprecated attribute. It also removes the JUCE_CATCH_DEPRECATED_CODE_MISUSE flag as we can rely on the override specifier catching usage of these old virtual methods, and tidies up the DOXYGEN preprocessor checks as they were inconsistent across the codebase.