impossible to link (ld / clang) liboping on macOS Big Sur 11 Beta

[sycured]

Describe the bug
Compilation fail

To Reproduce
Steps to reproduce the behavior:

1. add this line into ~/.config/nixpkgs/config.nix otherwise it's impossible to install on macOS:

( pkgs.liboping.overrideDerivation (old: {NIX_CFLAGS_COMPILE = "";} ) )

2. nix-env -i all

Expected behavior
Don't fail and arrive to do the linking (ld)

Output

building '/nix/store/0psa9x9abc3yhv4r2pnw44q0ywi15v4y-liboping-1.10.0.drv'...
unpacking sources
unpacking source archive /nix/store/x1f1kszhpxb4x4c8j9dqag614kyx56d6-liboping-1.10.0.tar.bz2
source root is liboping-1.10.0
setting SOURCE_DATE_EPOCH to timestamp 1494487978 of file liboping-1.10.0/src/mans/ping_iterator_get_info.3
patching sources
configuring
fixing libtool script ./ltmain.sh
configure flags: --disable-static --disable-dependency-tracking --prefix=/nix/store/s45i6bciaw48mv9s0xfwhh3m7vpiqy8s-liboping-1.10.0
checking for a BSD-compatible install... /nix/store/j0xbl8447zrk5f97d6w55d2l8qaldjxy-coreutils-8.31/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /nix/store/j0xbl8447zrk5f97d6w55d2l8qaldjxy-coreutils-8.31/bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking for gcc... clang
checking whether the C compiler works... no
configure: error: in `/private/var/folders/g5/ljjjnl3x4fq4x9tg69wy3lqh0000gn/T/nix-build-liboping-1.10.0.drv-0/liboping-1.10.0':
configure: error: C compiler cannot create executables
See `config.log' for more details
builder for '/nix/store/0psa9x9abc3yhv4r2pnw44q0ywi15v4y-liboping-1.10.0.drv' failed with exit code 77
cannot build derivation '/nix/store/qbsyr9i6wrv43rnfjdw9v2nf9kgav62f-all.drv': 1 dependencies couldn't be built
error: build of '/nix/store/qbsyr9i6wrv43rnfjdw9v2nf9kgav62f-all.drv' failed

Notify maintainers

Contributors from https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/libraries/liboping/default.nix:

• @fpletz
• @bjornfor
• @volth
• @OmnipotentEntity
• @globin
• @Ericson2314

Metadata
Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

• system: "x86_64-darwin"
• host os: Darwin 20.0.0, macOS 10.16
• multi-user?: no
• sandbox: no
• version: nix-env (Nix) 2.3.6
• channels(sycured): "nixpkgs-20.09pre231837.2cd2e7267e5"
• nixpkgs: /Users/sycured/.nix-defexpr/channels/nixpkgs

host os detected isn't real because it's macOS 11.0 Beta, not 10.16 :

[mroi]

This is a general issue on Big Sur and not specific to liboping. For example, I can also reproduce this using:

nix-build --check -A hello '<nixpkgs>'

The issue comes down to the new dyld cache and the subsequent removal of libraries from their usual filesystem locations. I am currently experimenting with updating the linker to address this issue. I will open a PR and mention it here, if I find a solution.

[mroi]

I updated the linker to version 530 from the cctools port used by Nix. This is the latest version Apple currently provides as open source. However, I cannot get simple C code to link with it. This is the error message:

ld: file not found: /usr/lib/system/libcache.dylib for architecture x86_64

The same object files link successfully with the linker shipping with Xcode 11.5 (ld version 556.6). It’s possible we have to wait until Apple releases this linker version’s source.

[mroi]

I created an overlay, with which I can successfully build the hello package on a Big Sur machine. It recruits the platform’s linker to do the actual work, so it is an ugly hack, but it works on first tests:

(self: super: {
	darwin = super.darwin // {
		cctools = super.darwin.cctools.overrideAttrs (attrs: {
			# workaround by using platform linker
			postInstall = ''
				rm $out/bin/ld
				cat <<- "EOF" > $out/bin/ld
					#!/bin/sh
					exec /usr/bin/ld -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk "$@"
				EOF
				chmod a+x $out/bin/ld
			'';
		});
	};
})

[sycured]

Not working

checking whether the C compiler works... no
configure: error: in `/private/var/folders/g5/ljjjnl3x4fq4x9tg69wy3lqh0000gn/T/nix-build-cctools-port.drv-0/source/cctools':
configure: error: C compiler cannot create executables
See `config.log' for more details
builder for '/nix/store/3j35kh281l86jrfwaahymy64f2svn6p5-cctools-port.drv' failed with exit code 77
cannot build derivation '/nix/store/nash3pyyz99vgqq5mrxk1d20sqcm1si8-Libsystem-osx-10.12.6.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/fnlcxyalmqgcnbsry94l74nc2v89fhiy-binutils-wrapper-2.31.1.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/8ffwdnrilnn3zsmcrqzn01w09hh6w3wb-bootstrap-stage2-clang-wrapper-.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/lgz47r57d8k3a6m1mv6cbpds9g2svanx-bootstrap-stage2-stdenv-darwin.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/rn7jxh4vx80by5l34r80zp2g22s6l624-bootstrap-stage2-stdenv-darwin.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/vzxd930xxgy44knvcfgkhnr5p82v1vn4-bootstrap-stage3-clang-wrapper-.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/apb4q462djzfj93pgjp66zksbfbfax64-bootstrap-stage3-stdenv-darwin.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/q6fzrm5wid7ivy9173vynnflmpia1g9z-bootstrap-stage3-stdenv-darwin.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/ixjkpmkwhxszb11y5dszsqkniz8kgahf-bootstrap-stage4-clang-wrapper-.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/qs2vqg24qma6r5g1ms077jr5h3blg1jk-cctools-binutils-darwin-wrapper-927.0.2.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/mf4z96pkyhj3i1rgxcjmzfllz305m6ja-clang-wrapper-5.0.2.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/sfxm7hvj3vzll75y1cbkdvv2l0x444jp-clang-wrapper-6.0.1.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/vhynnghj1qmany8mgh21a9cdzdgq9ymm-clang-wrapper-7.1.0.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/0mhv73mm2k6vq7xgy8a4gz8cl9ixxw5q-cmake-3.17.3.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/4yag260d3zfp5d6y5y8l5kkwz9rvgxaa-cmake-3.17.3.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/8fk1jnw24mzqc004c5lj5qli0fmjqbis-gcc-9.3.0.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/763nvn0vji4mljg2dyx87knh4pcji81f-perl-5.30.3.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/g72k2p18r5f8pb5ka7m37nc8xacfn5nf-perl-5.30.3.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/b2dhb60k122z3z8xkz8ja4mqm1jmjnmr-python-2.7.18.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/b1z965fh4lfpb7hpmi18mk4831ji34qq-stdenv-darwin.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/ixxvnwdrpgi7vf0pk1fiq6lfxq1aa410-stdenv-darwin.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/17j6hyfrfl6glmri6zb0lhgr5mf2y4l2-all.drv': 1 dependencies couldn't be built
error: build of '/nix/store/17j6hyfrfl6glmri6zb0lhgr5mf2y4l2-all.drv' failed

[mroi]

Yes, I forgot to explain that properly: You cannot bootstrap my workaround on Big Sur, since it tries to build my hacked cctools package with the current cctools linker, which will fail in the way you show. You need to build the stdenv on a pre-Big-Sur machine and then copy the closure over to the Big Sur machine.

[sycured]

Thank you, I'm trying with a VM (Catalina)

I received this message from Apple Feedback because I opened an issue before opening the issue in this github:

The macOS Big Sur has the following change that’s documented in the release notes -> https://developer.apple.com/documentation/macos-release-notes/macos-big-sur-11-beta-release-notes:

New in macOS Big Sur 11 beta, the system ships with a built-in dynamic linker cache of all system-provided libraries. As part of this change, copies of dynamic libraries are no longer present on the filesystem. Code that attempts to check for dynamic library presence by looking for a file at a path or enumerating a directory will fail. Instead, check for library presence by attempting to dlopen() the path, which will correctly check for the library in the cache.

This means that we no longer ship individual dylib files on disk. You should try passing in the -isysroot <PATH_TO_MACOS_SDK> flag to your clang link invocation.

[sycured]

I tried your overlay on Catalina and it's not working in my case

At each test, I obtain this error… @mroi have you an idea?

[mroi]

Could you give me a nix-build command to reproduce?

[sycured]

@mroi I tried nix-env -i ansible
But it's the same with nix-build -A ansible '<nixpkgs>'

[mroi]

I can reproduce the problem here. The newer linker version appears to be more picky regarding its options than the old one.
I guess this just shows how flaky this workaround is. :(

I think we just have to wait for Apple to update their linker’s source release and then integrate it step by step. Unless someone else has a better solution?

[sycured]

No idea excepted looking at https://opensource.apple.com/source/cctools/ and waiting the release of new version