Linux kernel syscalls expect to be given the number of bits of sigset that
they're built for, not the full 1024-bit sigsets that glibc supports.
I audited the other syscalls in here that use `sigset_t` and they're all
using `NSIG / 8`.
Fixes#12715
Translate-c didn't properly account for C macro functions having parameter names that are C keywords. So something like `#define FOO(float) ((float) + 10)` would've been interpreted as casting `+10` to a `float` type, instead of adding `10` to the parameter `float`.
An example of a real-world macro function like this is SDL3's `SDL_DEFINE_AUDIO_FORMAT` from `SDL_audio.h`, which uses `signed` as a parameter.
* If a function prototype is declarated inside a function, do not
translate it to a top-level extern function declaration. Similar to
extern local variable, just wrapped it into a block-local struct.
* Add a new extern_local_fn tag of aro_translate_c node for present
extern local function declaration.
* When a function body has a C function prototype declaration, it adds
an extern local function declaration. Subsequent function references
will look for this function declaration.
`wasm2c` uses an interesting mechanism to "fake" the existence of cache
directories. However, `wasi_snapshot_preview1_fd_seek` was not correctly
integrated with this system, so previously crashed when run on a file in
a cache directory due to trying to call `fseek` on a `FILE *` which was
`NULL`.
* When saving bigint limbs, we gave the iovec the wrong length, meaning
bigint data (and the following string and compile error data) was corrupted.
* When updating a stale ZOIR cache, we failed to truncate the file, so
just wrote more bytes onto the end of the stale cache.
This is actually completely well-defined. The resulting slice always has
0 elements. The only disallowed case is casting *to* a slice of a
zero-bit type, because in that case, you cna't figure out how many
destination elements to use (and there's *no* valid destination length
if the source slice corresponds to more than 0 bits).
