This new setup is slighly better on `silesia.tar` :
Ratio : 3.649 -> 3.655
Speed : 11.9 MB/s -> 12.2 MB/s
At the cost of more memory : 24 MB -> 32 MB
The new memory budget is a reasonable interpolation between neighboring levels 12 and 14:
level 12 : 24 MB
level 13 : 32 MB (increased from 24 MB)
level 14 : 48 MB
Window size remains unaffected (4 MB)

added qemu tests

Reduce test time on TravisCI

with optional success (for the time being)

that are being transfered to GA in #2758.
This represents a saving of ~25mn of cpu time on TravisCI.

2-bytes alignment is enough for 16-bit fields

running zstd library on emulated targets

since it fails on Github Actions specifically.

The test is run on TravisCI for the time being.
Its duration has been reduced to ~6mn anyway.

This was ~30mn, by far the longest run on travisCI.
That's because it re-analyzes multiple times the same files (library files notably).
It also performs actions that make no sense for the static analyzer purpose,
such as building the single-file library.

Reduced time spent in this test by reducing its scope :
just build the CLI, and obviously the library along it.
These are the only ones that really deserve to be analyzed.

Unfortunately, it still results in a number of false positives when using newer versions of scanbuild
(each version of scanbuild generates a different list of false positives).
These will have to be fixed before transfering to Github Actions.

by allowing parallel build of units,
and reducing optimization levels.

Parallel build is only effective on "recent" versions of `zstd`,
as previously, the list of units was passed as a list of source files,
which is something neither `make` nor `gcc` can parallelize.
So its impact is mildly effective (-20%).

Reducing optimization level to `-O1` makes compilation much faster.
It also makes runtime slower,
but in this test, compilation time dominates run time.
The savings are very significant (-50%).

On my test system, it reduces the length of this test from 13mn to 5mn.

[easy] Fix zstd bench error message

meson fixups

make ZSTD_HASHLOG3_MAX private

This is an implementation detail,
it doesn't belong to public space (zstd.h).

Improve branch misses on FSE symbol spreading

This matches the Makefile build. Due to one private xxhash symbol in use
by the program, it recompiles a private copy of xxhash.

Due to the test binaries making extensive (?) use of private symbols, it
doesn't even attempt to link to shared libzstd, and instead, all of the
original object files are added to libtestcommon itself for private
linkage. This, too, matches the Makefile build.

Ref. #2261

meson prefers that project-level options for Wall/Wextra/pedantic be
used, rather than hardcoding raw flags in add_project_arguments. If you
do the latter anyway, it raises a meson warning.

Set the default options for the project to use all this.

Also move the -Werror comment to the project default options with
appropriate format, but leave it commented out since it does not work.

This saves repeatedly compiling them, resulting in 16 fewer compile
steps, in exchange for one `ar` step.

[RFC] Rebalance compression levels

Set mtime on Output Files

[HUF] Improve Huffman sorting algorithm

This behavior of `touch` is standardized in POSIX, so it should be available.

[HUF] Improve Huffman encoding speed

* Add a Huffman round trip fuzzer
* Fix two minor bugs in Huffman that aren't exposed in zstd
  - Incorrect weight comparison (weights are allowed to be equal to
    table log).
  - HUF_compress1X_usingCTable_internal() can return compressed
    size >= source size, so the assert that `cSize <= 65535` isn't
    correct, and it needs to be checked instead.

[CI][2/2] Migrate CI tests which (currently) fail