This commit adds `dup2` and `dup3` based on musl. Zig already has
wrappers for the syscalls, but musl's implementation checks for a rare,
temporary race condition with dup2/3 and `open`. Like musl, this
implementation adds a fallback for dup3 if the syscall isn't available.
Contributes to: #30978
mingw,musl,wasi-libc: remove c files, that only provide functions already included in zigc
mingw: remove c files, that only provide functions, which are in ucrt
mingw: do not include mingw files/zigc functions on targets on which they in ucrt
The implementation was ported from `musl`. Unit tests for `f80` and `f128` were also added.
`__cosl` was already implemented in `trig.zig` while working on `sinl`.
The changes were tested by running:
```
$ ./build/stage3/bin/zig build -p stage4 -Denable-llvm -Dno-lib
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter='math.cosl' -fqemu -fwasmtime --summary line
Build Summary: 553/553 steps succeeded
```
The implementation was ported from `musl`. Unit tests for `f80` and `f128` were also added.
The changes were tested by running:
```
$ ./build/stage3/bin/zig build -p stage4 -Denable-llvm -Dno-lib
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=sinl -fqemu -fwasmtime --summary line
Build Summary: 553/553 steps succeeded
```
Seems like it was missed when implementing `rint`.
This was checked by running:
```
$ ./build/stage3/bin/zig build -p stage4 -Denable-llvm -Dno-lib
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=rint -fqemu -fwasmtime --summary line
Build Summary: 2209/2209 steps succeeded
```
The implementation was ported from `musl` to Zig code, and the `rint`
unit tests were generalized so they could be used for `rintf` as well.
This was checked both through unit tests and running `libc-test` suite:
```
$ ./build/stage3/bin/zig build -p stage4 -Denable-llvm -Dno-lib
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=rintf -fqemu -fwasmtime --summary line
Build Summary: 1657/1657 steps succeeded
```
The behaviour of `libc` `finite` functions is the same as Zig std's, so
the function basically delegates to `math.isFinite` and no new tests were
added. These functions are obsolete, but still part of `musl`.
No results are attached in this case as `libc-test` doesn't have tests for them.
The `frexp` implementation was generalized so it can be used for `f32`
and `c_longdouble` types as well.
The changes were tested by running:
```
$ ./build/stage3/bin/zig build -p stage4 -Denable-llvm -Dno-lib
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=frexp -fqemu -fwasmtime --summary line
Build Summary: 737/737 steps succeeded
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=frexpf -fqemu -fwasmtime --summary line
Build Summary: 369/369 steps succeeded
```
The changes were tested by running:
```
$ ./build/stage3/bin/zig build -p stage4 -Denable-llvm -Dno-lib
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=frexp -fqemu -fwasmtime --summary line
Build Summary: 737/737 steps succeeded
```
The tests were passing even when it was a straightforward calling of Zig
std library, but I wanted the `x is NaN` special case to match the
behaviour described in `libc` manpages, and for it to be consistent
with how infinities as arguments are handled in Zig.
`isastream` is an old, deprecated function for the STREAMS framework.
Linux doesn't even support this natively, and so the musl implementation
just returns 0 (not a STREAMS file) for valid file descriptors or -1
(for bad file descriptors).
`modf` function was generalized and renamed to `modfGeneric`, `modf` and
`modff` provide the appropriate type while calling that function. The
unit tests were also generalized so they can be reused for different
float types.
Both `modf` and `modff` were tested after making these changes:
```
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=modf -fqemu -fwasmtime --summary line
Build Summary: 921/921 steps succeeded
```
```
stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=modff -fqemu -fwasmtime --summary line
Build Summary: 369/369 steps succeeded
```
The behaviour regarding special cases differs between `libc` and Zig's
`stdlib` for `modf`, so the implementation couldn't be a straightforward
calling of `stdlib` function.
Other than the obvious documented differences, I also had problems with
the `INVALID` flag being raised while running `libc-test` suite on riscv
arch through qemu. The solution was to test if the argument is `NaN`,
and then return a quiet `NaN` if so.
Passing tests, that should include all the special cases to be wary of,
were also added.
Test results:
```
$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=modf -fqemu -fwasmtime --summary line
Build Summary: 921/921 steps succeeded
```
This commit removes `posix_fadvise`, `posix_fallocate`, and `fallocate`
from the bundled musl by forwarding to Zig's wrappers. `musl`'s
implemenation does not use `__syscall_cp`, so I assume trivially
replacing these functions is okay.
For `posix_fadvise`, `musl` notes that the arguments are reordered
for ARM and other architectures. Zig's wrapper already handles this
case.
Contributes toward: #30978
Alex Rønne Petersen