The files in this directory are from the FLAC 1.5.0 release downloaded in a tarball from
https://github.com/xiph/flac/releases/tag/1.5.0

They have been modified as little as possible, so that when they are included by
JUCE they compile without warnings and work correctly on the supported platforms.

Below I will refer to the contents of the tarball as RELEASE and to our repo as JUCE.

The steps carried out when including the 1.5.0 version
* The contents of RELEASE/include/FLAC and RELEASE/include/share were copied to
  JUCE/[..]/codecs/flac
* The contents of RELEASE/libFLAC were copied to JUCE/[..]/codecs/flac/libFLAC
* The includes in all these files were retargeted, to be relative to the file that does the
  including, so that we don't have to rely on e.g. flac/libFLAC/include being among the include
  directories, like it is when building FLAC with the official makefiles. All this retargeting is
  done per-line with a Python script. All the rules used for the retargeting can be seen in the code
  excerpt at [1].
* Then I will do a compile/test/modify loop, until it works and compiles without warnings. The
  changes made are mostly suppressing warnings.
* Then I delete all library files, and only re-add those that are needed for successful compilation.
  This delete step is propagated back to older commits, so that unneeded files are never added to
  the GIT repo.

In order to get the lpc_intrin_neon.c file to build with MSVC, a new function
'FLAC__build_int32x4_t' was added, and all braced initialisations of int32x4_t types were switched
to use the new function instead.

[1]: Code excerpt used for retargeting includes in the copied files
```
def transform(path: Path, line: str) -> str:
    if path.match("libFLAC/*"):
        line = line.replace('#include "private', '#include "include/private')
        line = line.replace('#include "protected', '#include "include/protected')
        line = line.replace('#include "share/', '#include "../')
        line = line.replace('#include "FLAC/', '#include "../')

    if path.match("libFLAC/include/private/*") or path.match(
        "libFLAC/include/public/*"
    ):
        line = line.replace('#include "share/', '#include "../../../')
        line = line.replace('#include "FLAC/', '#include "../../../')

    if path.match("*"):
        line = line.replace('#include "share/', '#include "')

    if path.match("libFLAC/include/private/*"):
        line = line.replace('#include "private/', '#include "')

    if path.match("libFLAC/include/protected/*"):
        line = line.replace('#include "private/', '#include "../private/')
        line = line.replace('#include "FLAC/', '#include "../../../')

    line = line.replace('#include "include/private/macros.h"', "")

    return line
```
