rust: fix on aarch64-linux by using GCC 11 and passing -lgcc

This change switches to using GCC 11 by default on aarch64-linux, as well as passing `-lgcc` to the linker, per NixOS#201485.

See NixOS#201254 and NixOS#208412 for wider context on the issue.

pkgs/build-support/rust/hooks/cargo-setup-hook.sh

@@ -1,6 +1,8 @@
 cargoSetupPostUnpackHook() {
     echo "Executing cargoSetupPostUnpackHook"
 
+    export NIX_LDFLAGS+=" @aarch64LinuxGccWorkaround@"
+
     # Some cargo builds include build hooks that modify their own vendor
     # dependencies. This copies the vendor directory into the build tree and makes
     # it writable. If we're using a tarball, the unpackFile hook already handles

pkgs/build-support/rust/hooks/default.nix

@@ -108,6 +108,9 @@ in {
           host-config = true
           target-applies-to-host = true
         '';
+
+        # https://github.com/NixOS/nixpkgs/issues/201254
+        aarch64LinuxGccWorkaround = lib.optionalString (stdenv.isLinux && stdenv.isAarch64 && stdenv.cc.isGNU) "-lgcc";
       };
     } ./cargo-setup-hook.sh) {};
 

pkgs/development/compilers/rust/rustc.nix

@@ -52,7 +52,9 @@ in stdenv.mkDerivation rec {
        # when linking stage1 libstd: cc: undefined reference to `__cxa_begin_catch'
        optional (stdenv.isLinux && !withBundledLLVM) "--push-state --as-needed -lstdc++ --pop-state"
     ++ optional (stdenv.isDarwin && !withBundledLLVM) "-lc++"
-    ++ optional stdenv.isDarwin "-rpath ${llvmSharedForHost}/lib");
+    ++ optional stdenv.isDarwin "-rpath ${llvmSharedForHost}/lib"
+       # https://github.com/NixOS/nixpkgs/issues/201254
+    ++ optional (stdenv.isLinux && stdenv.isAarch64 && stdenv.cc.isGNU) "-lgcc");
 
   # Increase codegen units to introduce parallelism within the compiler.
   RUSTFLAGS = "-Ccodegen-units=10";

pkgs/top-level/all-packages.nix

@@ -15386,6 +15386,8 @@ with pkgs;
   rust_1_66 = callPackage ../development/compilers/rust/1_66.nix {
     inherit (darwin.apple_sdk.frameworks) CoreFoundation Security SystemConfiguration;
     llvm_14 = llvmPackages_14.libllvm;
+    # https://github.com/NixOS/nixpkgs/issues/201254
+    stdenv = if stdenv.isLinux && stdenv.isAarch64 && stdenv.cc.isGNU then gcc11Stdenv else stdenv;
   };
   rust = rust_1_66;