glibc: fix build vs host tool confusion

[thefloweringash]

Motivation for this change

Cross compilation from aarch64-linux -> armv7l-linux

#106759 (comment)

Edit: Upstream issue by @Ericson2314: https://sourceware.org/bugzilla/show_bug.cgi?id=23681

I don't know how this (source) is meant to work, or if it works elsewhere, so this is a very blunt solution. More elegant solutions very welcome. The -print-prog-name= flag to gcc (source) is a general search through a list of directories for the provided binary (with a couple of exceptions), for example:

$ strace $CC -print-prog-name=BANANAPHONE 2>&1 | grep BANANAPHONE
execve("/nix/store/ndwv24mf56w15hak6b4bi5nlzsc1qsjg-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-wrapper-10.2.0/bin/armv7l-unknown-linux-gnueabihf-gcc", ["armv7l-unknown-linux-gnueabihf-g"..., "-print-prog-name=BANANAPHONE"], 0xfffff1921018 /* 192 vars */) = 0
execve("/nix/store/8cxq0frw1lwkfv1whzg87xz22yw7mgpk-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0/bin/armv7l-unknown-linux-gnueabihf-gcc", ["/nix/store/8cxq0frw1lwkfv1whzg87"..., "-fno-strict-overflow", "-Wformat", "-Wformat-security", "-Werror=format-security", "-fPIC", "-march=armv7-a", "-mfpu=vfpv3-d16", "-print-prog-name=BANANAPHONE", "-B/nix/store/wsyl89si5yimrl4ajij"..., "-B/nix/store/ndwv24mf56w15hak6b4"..., "-Wno-error=missing-attributes", "-ggdb", "-Wa,--compress-debug-sections", "-frandom-seed=4fhs4fj3y5", "-isystem", "/nix/store/3wdvnp51dv9v6r56zadj1"...], 0x2d8e0008 /* 209 vars */) = 0
newfstatat(AT_FDCWD, "/nix/store/wsyl89si5yimrl4ajijpnlz9545kk7ny-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0-lib/armv7l-unknown-linux-gnueabihf/lib/armv7l-unknown-linux-gnueabihf/10.2.0/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/wsyl89si5yimrl4ajijpnlz9545kk7ny-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0-lib/armv7l-unknown-linux-gnueabihf/lib/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/ndwv24mf56w15hak6b4bi5nlzsc1qsjg-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-wrapper-10.2.0/bin/armv7l-unknown-linux-gnueabihf/10.2.0/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/ndwv24mf56w15hak6b4bi5nlzsc1qsjg-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-wrapper-10.2.0/bin/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/8cxq0frw1lwkfv1whzg87xz22yw7mgpk-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0/libexec/gcc/armv7l-unknown-linux-gnueabihf/10.2.0/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/8cxq0frw1lwkfv1whzg87xz22yw7mgpk-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0/libexec/gcc/armv7l-unknown-linux-gnueabihf/10.2.0/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/8cxq0frw1lwkfv1whzg87xz22yw7mgpk-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0/libexec/gcc/armv7l-unknown-linux-gnueabihf/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/8cxq0frw1lwkfv1whzg87xz22yw7mgpk-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0/lib/gcc/armv7l-unknown-linux-gnueabihf/10.2.0/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/8cxq0frw1lwkfv1whzg87xz22yw7mgpk-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0/lib/gcc/armv7l-unknown-linux-gnueabihf/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/8cxq0frw1lwkfv1whzg87xz22yw7mgpk-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0/lib/gcc/armv7l-unknown-linux-gnueabihf/10.2.0/../../../../armv7l-unknown-linux-gnueabihf/bin/armv7l-unknown-linux-gnueabihf/10.2.0/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/nix/store/8cxq0frw1lwkfv1whzg87xz22yw7mgpk-armv7l-unknown-linux-gnueabihf-stage-static-gcc-debug-10.2.0/lib/gcc/armv7l-unknown-linux-gnueabihf/10.2.0/../../../../armv7l-unknown-linux-gnueabihf/bin/BANANAPHONE", 0xffffc08d57a8, 0) = -1 ENOENT (No such file or directory)
write(1, "BANANAPHONE\n", 12BANANAPHONE

I don't expect any of these directories to contain tools from binutils.

cc @misuzu @TredwellGit @Ericson2314

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS (aarch64-linux -> armv7l-linux)
  • 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 nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Added a release notes entry if the change is major or breaking
• Fits CONTRIBUTING.md.

[misuzu]

LGTM! The only thing that is failing to build for me is the Linux kernel, but it's most likely unrelated:

error: builder for '/nix/store/66r6q1d0wr10iz68i77qzfgrhfb2y5zk-linux-armv7l-unknown-linux-gnueabihf-5.12.7.drv' failed with exit code 1;
       last 10 log lines:
       >   MODPOST vmlinux.symvers
       >   MODINFO modules.builtin.modinfo
       >   GEN     modules.builtin
       >   LD      .tmp_vmlinux.kallsyms1
       > /nix/store/69v26s02bc8lqpflhc95rqn1gczv6dc2-armv7l-unknown-linux-gnueabihf-binutils-2.35.1/bin/armv7l-unknown-linux-gnueabihf-ld: warning: unrecognized --build-id style ignored
       > /nix/store/69v26s02bc8lqpflhc95rqn1gczv6dc2-armv7l-unknown-linux-gnueabihf-binutils-2.35.1/bin/armv7l-unknown-linux-gnueabihf-ld: drivers/net/ethernet/micrel/ks8851_common.o: in function `ks8851_probe_common':
       > ks8851_common.c:(.text+0x179c): undefined reference to `__this_module'
       > /nix/store/69v26s02bc8lqpflhc95rqn1gczv6dc2-armv7l-unknown-linux-gnueabihf-binutils-2.35.1/bin/armv7l-unknown-linux-gnueabihf-ld: ks8851_common.c:(.text+0x17a0): undefined reference to `__this_module'
       > make[1]: *** [/build/linux-5.12.7/Makefile:1199: vmlinux] Error 1
       > make: *** [../Makefile:215: __sub-make] Error 2
       For full logs, run 'nix log /nix/store/66r6q1d0wr10iz68i77qzfgrhfb2y5zk-linux-armv7l-unknown-linux-gnueabihf-5.12.7.drv'.

[thefloweringash]

There’s a fix for the kernel linker failure: https://patchwork.kernel.org/project/netdevbpf/patch/[email protected]/

[github-actions]

Successfully created backport PR #126442 for release-21.05.