Blosc

- Fixed a regression in 1.16.0 that prevented to compress empty buffers
(see 260).

- Zstd updated to 1.3.8 (from 1.3.7).

- Now the functions that execute Blosc decompressions are safe by default
for untrusted/possibly corrupted inputs. The additional checks seem to
not affect performance significantly (see some benchmarks in 258), so
this is why they are the default now.

The previous functions (with less safety) checks are still available with a
'_unsafe' suffix. The complete list is:

- blosc_decompress_unsafe()
- blosc_decompress_ctx_unsafe()
- blosc_getitem_unsafe()

Also, a new API function named blosc_cbuffer_validate(), for validating Blosc
compressed data, has been added.

For details, see PR 258. Thanks to Jeremy Maitin-Shepard.

- Fixed a bug in `blosc_compress()` that could lead to thread deadlock under
some situations. See 251. Thanks to wenjuno for the report and the fix.

- Fix data race in shuffle.c host_implementation initialization. Fixes 253.
Thanks to Jeremy Maitin-Shepard.

This is a maintenance release that adds a workaround for Visual Studio
2008's lack of a stdint.h file to blosclz.c.

For more info, please see the release notes in:

https://github.com/Blosc/c-blosc/blob/master/RELEASE_NOTES.rst

In this release, the `blosc_compress()` and `blosc_decompress()` interfaces
are now fork-safe, preventing child-process deadlocks in fork-based
multiprocessing applications. These interfaces with BLOSC_NOLOCK were, and
continue to be, fork-safe. `_ctx` interface context reuse continues to be
unsafe in the child process post-fork. Thanks to Alex Ford.

Also, a few bugs have been fixed, more compatibility with oldish compilers
and LZ4 and Zstd codecs have been updated to their latest versions.

For more info, please see the release notes in:

https://github.com/Blosc/c-blosc/blob/master/RELEASE_NOTES.rst

=============================

- Added a new `DEACTIVATE_SSE2` option for cmake that is useful for disabling
SSE2 when doing cross-compilation (see 236).

- New check for detecting output buffers smaller than BLOSC_MAX_OVERHEAD.
Fixes 234.

- The `complib` and `version` parameters for `blosc_get_complib_info()` can be
safely set to NULL now. This allows to call this function even if the user is
not interested in these parameters (so no need to reserve memory for them).
Fixes 228.

- In some situations that a supposedly blosc chunk is passed to
`blosc_decompress()`, one might end with an `Arithmetic exception`. This
is probably due to the chunk not being an actual blosc chunk, and divisions
by zero might occur. A protection has been added for this. See 237.

The main change for this release is that the pthreads library is
not needed on any Windows build anymore. Thanks to Steven G. Johnson.
Also, the internal Zstd sources have been updated to 1.3.4; expect
an important performance boost (can be up to 10%, specially for low
compression levels).

For more info, please see the release notes in:

https://github.com/Blosc/c-blosc/blob/master/RELEASE_NOTES.rst