This changes a bunch of things that allows building with the musl C lib,
provided that `libucontext-dev` and `pkg-config` are installed.
Note that installing libucontext makes absolutely zero sense on C libs
that do natively provide this deprecated System V API, such as glibc.
Hence, it no sane glibc setup is expected to ever have libucontext
installed.
A main pain point was that argv and argc are expected to be passed to
init_fini handlers, but that is actually a glibc extension. This just
parses `/proc/self/cmdline` by hand to populate argv and argc during
startup, unless running on glibc.
Initial version to test 64 bit compatibility.
Instead of a separate board, the inital version for Linux/x86_64 is enabled
by setting the environment variable `NATIVE_64BIT=y` and compiling as usual.
Not currently implemented:
* Architectures other than x86_64 or operating systems other than Linux
* No FreeBSD support
* No Aarch support
* Rust support for x86_64
Unaligned accesses on x86(_64) are allowed, but slow. However, some host systems
might not be that forgiving. Aligning the stack to sizeof(uintptr_t) should be
a pretty safe safety measure.
And with this done, all casts of the stack pointer that increase alignment
requirements are now intermediately casted to `uintptr_t` to silence
warnings from -Wcast-align - after all the stacks are now manually aligned.
On `native` the functions stdio_read() / stdio_write() were not
used.
Those functions are intended for alternative stdio implementations.
As a result, no alternative stdio could be used on `native`.
To fix this, call the functions in `_native_read()` / `_native_write()`
when dealing with stdio fds.
select() can not listen to POLLPRI events which are used by the
Kernel's GPIO API.
In preparation for that, rewrite async_read() to use poll() instead
of select().
Without this change a RIOT application compiled with all-asan will
segfault as RIOT provides its own malloc by default. Add a define for
disabling custom malloc, calloc and realloc implementations and use it
when compiling with all-asan.
External packages that may use fprintf(stderr, ...) for logging will
link directly to the libc version of it, and for some reason that
results in the application crashing.
In order to make native behave more similar to other platforms, it should also use TLSF's dynamic memory allocation if included. It will still fall back to the system's malloc implementation when building for use with valgrind, to leverage its memory leak detection mechanisms.
