* Add configs that test multithreading, LDM, and setting explicit
  parameters.
* Update the `compress cctx` method to accept `ZSTD_parameters`.
* Compile against the multithreaded `libzstd.a`.
* Update `results.csv` for the new configs.

Unless you think there are more configs/methods I should test, I think
we have a fairly wide set of configs/methods, so I'll pause adding
more for now.

[zstdcli] Refuse to overwrite input file

Compare the input and output files by their inode number and
refuse to open the output file if the input file is the same.

This doesn't work when (de)compressing multiple files to a single
file, but that is a very uncommon use case, mostly used for
benchmarking by me.

Fixes #1422.

[libzstd] Fix estimate with negative levels

btultra2 and very small input

* Fix `ZSTD_estimateCCtxSize()` with negative levels.
* Fix `ZSTD_estimateCStreamSize()` with negative levels.
* Add a unit test to test for this error.

as reported by @terrelln.
2 is reserved for temporary usage only.

When srcSize is small,
the nb of symbols produced is likely too small to warrant dedicated probability tables.
In which case, predefined distribution tables will be used instead.

There is a cheap algorithm in btultra initialization :
it presumes default distribution will be used if srcSize <= 1024.

btultra2 now uses the same threshold to shut down probability estimation,
since measured frequencies won't be used at entropy stage,
and therefore relying on them to determine sequence cost is misleading,
resulting in worse compression ratios.

This fixes btultra2 performance issue on very small input.

Note that, a proper way should be
to determine which symbol is going to use predefined probaility
and which symbol is going to use dynamic ones.
But the current algorithm is unable to make a "per-symbol" decision.
So this will require significant modifications.

overlapLog default values

Add multiple_simple_compression.c (demonstrates the use of ZSTD_compressCCtx(...)) to examples directory.

break loadFile_orDie() into 2: loadFile_orDie() loads file into a pre-allocated memory buffer, mallocAndLoadFile_orDie() allocates memory first, then calls loadFile_orDie()

Factor out allocMemory_orDIe(...) in simple_compressionCCtx.c, and amend Makefile to account for dependency on utils.h

meson: Remove unused sys import

[zstdcli] Add --no-progress flag

The `--no-progress` flag disables zstd's progress bars, but leaves
the summary.

I've added simple tests to `playTests.sh` to make sure the parsing
works.

meson: More accurate Windows build support

with correct pointer type

[libzstd] Fix infinite loop in decompression

When we switched `ZSTD_SKIPPABLEHEADERSIZE` to a macro, the places where we do:

    MEM_readLE32(ptr) + ZSTD_SKIPPABLEHEADERSIZE

can now overflow `(unsigned)-8` to `0` and we infinite loop. We now check
the frame size and reject sizes that overflow a U32.

Note that this bug never made it into a release, and was only in the dev branch
for a few days.

Credit to OSS-Fuzz

from 64-bit to 32-bit

travis: Use script instead of Cmd env

Let soversion base on version if not set. For example, if version is 3.6.0
and soversion is not defined, it is set to 3.

Use MESON_INSTALL_DESTDIR_PREFIX variable instead of DESTDIR.