`CFLAGS=-O0 make`
will now use `-O0` instead of enforcing `-O3`
which used to be the behavior before introduction of `libzstd.mk`.
This should result in faster tests,
since a few tests depend on this capability for faster roundtrips.
Move portability macros to `lib/common/portability_macros.h`. This file
only contains platform/feature detection (e.g. 0/1 macros). This file is
shared between C and ASM code, so it cannot include any C code.
Rename `HUF_` ASM macros to be `ZSTD_` prefixed, and move to the new
header.
Restrict `ZSTD_ASM_SUPPORTED` to `__GNUC__`, because we need the GAS
assembler.
Finally, only include the ASM code if we are actually going to use it.
This disables it on all Windows platforms, which should resolve the
problem brought up in Issue #2789.
* Extract out common portion of `lib/Makefile` into `lib/libzstd.mk`.
Most relevantly, the way we find library files.
* Use `lib/libzstd.mk` in the other Makefiles instead of repeating the
same code.
* Add a test `tests/test-variants.sh` that checks that the builds of
`make -C programs allVariants` are correct, and run it in Actions.
* Adds support for ASM files in the CMake build.
The Meson build is not updated because it lists every file in zstd,
and supports ASM off the bat, so the Huffman ASM commit will just add
the ASM file to the list.
The Visual Studios build is not updated because I'm not adding ASM
support to Visual Studios yet.
Nick Terrell