I wanted to install a Linux-targetting compiler on a Darwin (macOS) host. The compiler part actually works out-of-the-box with Nixpkgs, which I found quite impressive. However, building glibc on macOS fails with multiple successive errors. I have fixed them and can now build and install a x86_64-linux and i686-linux compiler on macOS.

I decided to put all my changes into a patch file so I do not pollute the Linux builds of glibc. The changes are documented at the top of the patch file. I will copy those notes here for completeness:

• increase ulimit for open files: macOS default of 256 is too low for glibc build system
• use host version of ar, which is given by environment variable
• build system uses stamp.os and stamp.oS files, which only differ in case; this fails on macOS, so replace .oS with .o_S
• libintl.h does not exist (and is not needed) on macOS

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.