Apparently, Options.o cannot be linked in without $(PROGDIR)/util.o

Cmake set default build type

BUG: list sub-command REMOVE_DUPLICATES requires list to be present

travis: Use ninja from official github release

meson: Update build guide

meson: Correct generating pkgconf after Meson v0.49.0

Fix remaining Windows errors

due to bad support of inode identifiers.
On Visual, option is limited to same file name,
which is imperfect, but way better than disabling the feature entirely.

It's enough to pass associated tests.

On Windows, the equivalent of `/dev/null` is `NUL`.
When tests are run under msys2/minGW,
the environment identifies itself as Windows,
hence the script uses `NUL` instead of `/dev/null`
but the environment will consider `NUL` to be a regular file name.
Consequently, `NUL` will be overwritten during tests,
triggering an error.

This patch uses flag `-f` to force such overwrite
passing the test.

ENH: Update to -DZSTD_LEGACY_SUPPORT=5

When compiling without c++ enabled, some variables are not present.
This is a check enforced in recent Cmake versions.

CMake Error at CMakeModules/AddZstdCompilationFlags.cmake:54 (list):
  list sub-command REMOVE_DUPLICATES requires list to be present.
Call Stack (most recent call first):
  CMakeLists.txt:53 (ADD_ZSTD_COMPILATION_FLAGS)

The CMAKE_BUILD_TYPE variable is a CACHE variable
and should be set in a way that persists and is
documented in the CACHE.  Also set the default
values for the gui to ease selection of types.

These changes provide better support for GUI
configurators that support cmake.

bench.c => benchfn.c + benchzstd.c
wrong util.c from prior patch

and warnings :
C4127

which will execute same tests as `master` branch
hence including older Visual version

Unified travis.yml

fixed tests for minimal decoder builds

to reduce test time for dev

Modernize cmake syntax

It's incorrect to mix targets `all` and `check` with directive -j.
They will be build in parallel
and resulting artifacts will fight each other
with different sets of build options (such as DEBUGLEVEL).

guard functions using floating point for debug mode only

fix confusion between unsigned <-> U32

update travis test 

Ancient versions of CMake required else(), endif(), and similar block
termination commands to have arguments matching the command starting the block.
This is no longer the preferred style.

Ancient CMake versions required upper-case commands.  Later command names
became case-insensitive.  Now the preferred style is lower-case.

they are only used to print debug messages.
Requested in #1386,

as suggested in #1441.

generally U32 and unsigned are the same thing,
except when they are not ...

case : 32-bit compilation for MIPS (uint32_t == unsigned long)

A vast majority of transformation consists in transforming U32 into unsigned.
In rare cases, it's the other way around (typically for internal code, such as seeds).

Among a few issues this patches solves :
- some parameters were declared with type `unsigned` in *.h,
  but with type `U32` in their implementation *.c .
- some parameters have type unsigned*,
  but the caller user a pointer to U32 instead.

These fixes are useful.

However, the bulk of changes is about %u formating,
which requires unsigned type,
but generally receives U32 values instead,
often just for brevity (U32 is shorter than unsigned).
These changes are generally minor, or even annoying.

As a consequence, the amount of code changed is larger than I would expect for such a patch.

Testing is also a pain :
it requires manually modifying `mem.h`,
in order to lie about `U32`
and force it to be an `unsigned long` typically.
On a 64-bit system, this will break the equivalence unsigned == U32.
Unfortunately, it will also break a few static_assert(), controlling structure sizes.
So it also requires modifying `debug.h` to make `static_assert()` a noop.
And then reverting these changes.

So it's inconvenient, and as a consequence,
this property is currently not checked during CI tests.
Therefore, these problems can emerge again in the future.

I wonder if it is worth ensuring proper distinction of U32 != unsigned in CI tests.
It's another restriction for coding, adding more frustration during merge tests,
since most platforms don't need this distinction (hence contributor will not see it),
and while this can matter in theory, the number of platforms impacted seems minimal.

Thoughts ?

in an attempt to circumvent the `ld` bug

fixed : better error message

[regression] Update results.csv