https://buildd.debian.org/status/package.php?p=rust-mach-o-sys
shows that many debian platforms are failing to build.
The failures mostly look like this:
```
581 | pub const BIND_SPECIAL_DYLIB_FLAT_LOOKUP: ::std::os::raw::c_char = -2;
| ^^ cannot apply unary operator `-`
|
= note: unsigned values cannot be negated
```
I think they're happening on platforms where char is unsigned by
default.
Given that mach-o-sys is really intended for the OS X platform, it isn't
surprising that it's failing.
However, this causes memsec to be BD-uninstallable on those same
architectures.
The only reason i can see for having rust-mach-o-sys in debian is for
the ability to cross-compile to MacOS. But I've never tried to do that,
and maybe it's not actually possible.
Anyway, i'm tempted to carve it out from rust-memsec, since it's only
relevant there:
https://codesearch.debian.net/search?q=mach.o.sys&literal=0&perpkg=1
If we do carve it out of rust-memsec, we might want to just remove
rust-mach-o-sys from debian until someone has a concrete need for it.