getifaddrs linked with musl libc hangs on big-endian targets
## Host environment
- Operating system: Ubuntu
- OS/kernel version: `Linux 6.7.0 #1 SMP PREEMPT_DYNAMIC Mon Jan 22 07:51:29 CST 2024 x86_64 x86_64 x86_64 GNU/Linux`
- Architecture: x86_64
- QEMU flavor: `qemu-m68k` (likely big-endian targets)
- QEMU version: `qemu-m68k version 8.1.50 (v8.1.0-83-g50e7a40af3-dirty)`
- QEMU command line: n/a (qemu-user)
## Emulated/Virtualized environment
- Operating system: n/a
- OS/kernel version: n/a (see above)
- Architecture: m68k, ppc, ppc64, s390x (likely but untested: or1k, sparc\*)
## Description of problem
When the following C program (borrowed from curl's `configure`) is compiled for { m68k, ppc, ppc64, s390x } (possibly others, like or1k and sparc) and linked against musl libc, it hangs inside musl when run. Copying the same binaries to real hardware results in success.
```c
#include <stdlib.h>
#include <ifaddrs.h>
int
main (void)
{
struct ifaddrs *ifa = 0;
int error;
error = getifaddrs(&ifa);
if (error || !ifa)
exit(1);
else
exit(0);
return 0;
}
```
## Steps to reproduce
1. Compile the above program and link it with musl libc (pre-built toolchains are available [here](https://musl.cc/))
2. Run the appropriate `qemu-*` (e.g. `qemu-m68k ./test` or `qemu-ppc ./test`)
3. Observe that the process hangs.
## Additional information
This has come up elsewhere:
* https://bugs.gentoo.org/914256
* https://www.openwall.com/lists/musl/2018/05/30/4
* Likely affects or1k but I can't test that at the moment (need to debug an unrelated issue with that toolchain)
* Likely affects sparc but that port/toolchain is also a WIP
Here are some static sample binaries for the above program:
* https://temp.zv.io/qemu-bug.tar.xz (no guarantees of continued existence months or years later)
GitLab labels seem to be missing:
* ~"kind::Bug"
* ~"linux-user"
* ~"target: ppc"
* ~"target: m68k"
* ~"target: s390x"
issue