Factor out platforms for which libc is empty
This change shouldn't change any functionality. It just separates the platforms for which `libc` is currently empty (only `wasm32-unknown-unknown`), from those for which it isn't. This is a non-functional change.
Use OR in the license field
According to [The Manifest Format](https://doc.rust-lang.org/cargo/reference/manifest.html):
>Multiple licenses can be separated with a `/`, although that usage is deprecated. Instead, use a license expression with AND and OR operators to get more explicit semantics.
Linux 4.18 added support for SIGSYS info in signalfd. Add the new
fields to signalfd_siginfo.
While the kernel has support for these new fields now, no libc has
shipped a release with the new signalfd fields.
Add F_RDLCK/F_WRLCK/F_UNLCK to several platforms
These are used by the flock wrapper in rustc_data_structures. The constants were already present in x86_64-linux-gnu and BSD (since 4928bd9869).
Currently the `flock` wrapper in `rustc_data_structures` does not work on several 32-bit musl targets, because they expect the `LARGEFILE64` version of the `F_SETLK`/`F_SETLKW` constants. This PR is a prerequisite to converting that code to use the `libc` types and constants, instead of (inaccurately) duplicating them, since `libc` already provides architecture-specific definitions of the relevant constants.
Add extattr(2) and extattr(3) definitions for FreeBSD and NetBSD
DragonflyBSD does define 3 of these 14 functions. But I elected not to
add it to the PR because I can't find any evidence that these syscalls
are used on Dragonfly, even in the base system. And by themselves,
those three are insufficient for the xattr crate.
DragonflyBSD does define 3 of these 14 functions. But I elected not to
add it to the PR because I can't find any evidence that these syscalls
are used on Dragonfly, even in the base system. And by themselves,
those three are insufficient for the xattr crate.
Add CMSG macros for unix/bsd and unix/notbsd
This adds the ["Ancillary Data Object Macros" from RFC 2292](https://tools.ietf.org/html/rfc2292#section-4.3). My C's weak but I think I've translated them faithfully. Tested on macOS and Linux/glibc.
