Support alternative platform detection mechanisms other than reading /bin/ls

[robin-nitrokey]

The find_libc function that is used to determine whether uv is running on musllinux or manylinux tries to read /bin/ls:

uv/crates/platform-host/src/linux.rs

Lines 128 to 141 in c6a43e9

	/// Find musl libc path from executable's ELF header.
	fn find_libc() -> Result<PathBuf, PlatformError> {
	let buffer = fs::read("/bin/ls")?;
	let error_str = "Couldn't parse /bin/ls for detecting the ld version";
	let elf = Elf::parse(&buffer)
	.map_err(|err| PlatformError::OsVersionDetectionError(format!("{error_str}: {err}")))?;
	if let Some(elf_interpreter) = elf.interpreter {
	Ok(PathBuf::from(elf_interpreter))
	} else {
	Err(PlatformError::OsVersionDetectionError(
	error_str.to_string(),
	))
	}
	}

If /bin/ls does not exist, uv cannot be run. This is the case namely on NixOS which does not follow the Filesystem Hierarchy Standard. I understand that this is a special case, but it would be great if you would provide a way to skip this check, e. g. by setting an environment variable (or maybe using /bin/sh instead which is available on NixOS).

[zanieb]

Thanks for the clear report!

[zanieb]

If you patch this to read /bin/sh does it "just work"?

[robin-nitrokey]

Yes, with /bin/sh it works for me.