libc-rs/src/unix/no_align.rs

s! {
    pub struct in6_addr {
        pub s6_addr: [u8; 16],
        __align: [u32; 0],
    }
}
Fix build on all platforms This PR fixes the build on all platforms and all Rust version down to the minimum Rust version supported by libc: Rust 1.13.0. The `build.rs` is extended with logic to detect the newer Rust features used by `libc` since Rust 1.13.0: * Rust 1.19.0: `untagged_unions`. APIs using untagged unions are gated on `cfg(libc_unions)` and not available on older Rust versions. * Rust 1.25.0: `repr(align)`. Because `repr(align)` cannot be parsed by older Rust versions, all uses of `repr(align)` are split into `align.rs` and `no_align.rs` modules, which are gated on the `cfg(libc_align)` at the top level. These modules sometimes contain macros that are expanded at the top level to avoid privacy issues (`pub(crate)` is not available in older Rust versions). Closes #1242 . * Rust : `const` `mem::size_of`. These uses are worked around with hardcoded constants on older Rust versions. Also, `repr(packed)` structs cannot automatically `derive()` some traits like `Debug`. These have been moved into `s_no_extra_traits!` and the lint of missing `Debug` implementations on public items is silenced for these. We can manually implement the `extra_traits` for these in a follow up PR. This is tracked in #1243. Also, `extra_traits` does not enable `align` manually anymore. Since `f64::to_bits` is not available in older Rust versions, its usage has been replaced with a `transmute` to an `u64` which is what that method does under the hood. Closes #1232 . 2019-02-07 11:37:21 +01:00			`s! {`
			`pub struct in6_addr {`
			`pub s6_addr: [u8; 16],`
			`__align: [u32; 0],`
			`}`
			`}`