Test nix builds

Installations on MacOS didn't properly work after 8ee7ab3 because MacOS
doesn't like the `-rpath=x` syntax.

The changed patch makes clang invocations compatible with both Linux and
MacOS. Added regression testing to CI so that we don't overlook issues
like this in the future.

Fixes #918

Co-authored-by: Zach Birenbaum <[email protected]>

.github/workflows/nix.yaml

@@ -80,3 +80,29 @@ jobs:
         run: >
           nix develop --impure --command
           bash -c "cargo test --all --profile=smol"
+
+  installation:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-22.04, macos-13, macos-14]
+    name: Installation / ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 45
+    steps:
+
+      - name: Checkout
+        uses: >- # v4.1.1
+          actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+
+      - name: Install Nix
+        uses: >- # v10
+          DeterminateSystems/nix-installer-action@de22e16c4711fca50c816cc9081563429d1cf563
+
+      - name: Cache Nix derivations
+        uses: >- # v4
+          DeterminateSystems/magic-nix-cache-action@fc6aaceb40b9845a02b91e059ec147e78d1b4e41
+
+      - name: Run build
+        run: >
+          nix build

local-remote-execution/generated-cc/cc/BUILD

@@ -111,18 +111,18 @@ cc_toolchain_config(
     coverage_link_flags = ["--coverage"],
     cpu = "k8",
     cxx_builtin_include_directories = [
-        "/nix/store/vqbgiwjvjbgypsfwgpdc78asxvx13lsm-clang-wrapper-18.1.5/resource-root/include",
+        "/nix/store/5ark5p94q2nwni9rkq9zqnfsyfv9y50w-clang-wrapper-18.1.5/resource-root/include",
         "/nix/store/s3pvsv4as7mc8i2nwnk2hnsyi2qdj4bq-glibc-2.39-31-dev/include",
-        "/nix/store/vqbgiwjvjbgypsfwgpdc78asxvx13lsm-clang-wrapper-18.1.5/resource-root/share",
+        "/nix/store/5ark5p94q2nwni9rkq9zqnfsyfv9y50w-clang-wrapper-18.1.5/resource-root/share",
         "/nix/store/csml9b5w7z51yc7hxgd2ax4m6vj36iyq-libcxx-18.1.5-dev/include/c++/v1",
         "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk",
     ],
     cxx_flags = ["-std=c++14"],
     dbg_compile_flags = ["-g"],
     host_system_name = "x86_64-unknown-linux-gnu",
     link_flags = [
-        "-fuse-ld=/nix/store/vqbgiwjvjbgypsfwgpdc78asxvx13lsm-clang-wrapper-18.1.5/bin/ld.mold",
-        "-B/nix/store/6fr9bp9drswk1azlcby44c97l9xiifbm-customClang/bin",
+        "-fuse-ld=/nix/store/5ark5p94q2nwni9rkq9zqnfsyfv9y50w-clang-wrapper-18.1.5/bin/ld.mold",
+        "-B/nix/store/d6x389rgl2x9b6dkwxc71grbzgmkr28c-customClang/bin",
         "-Wl,-no-as-needed",
         "-Wl,-z,relro,-z,now",
     ],
@@ -152,7 +152,7 @@ cc_toolchain_config(
         "llvm-cov": "None",
         "llvm-profdata": "None",
         "cpp": "/usr/bin/cpp",
-        "gcc": "/nix/store/6fr9bp9drswk1azlcby44c97l9xiifbm-customClang/bin/customClang",
+        "gcc": "/nix/store/d6x389rgl2x9b6dkwxc71grbzgmkr28c-customClang/bin/customClang",
         "dwp": "/nix/store/bmmczrsfycv4rradx0cy95vw0fwx9sm7-binutils-wrapper-2.41/bin/dwp",
         "gcov": "None",
         "nm": "/nix/store/bmmczrsfycv4rradx0cy95vw0fwx9sm7-binutils-wrapper-2.41/bin/nm",

local-remote-execution/generated-cc/cc/builtin_include_directory_paths

@@ -1,11 +1,11 @@
 This file is generated by cc_configure and contains builtin include directories
-that /nix/store/6fr9bp9drswk1azlcby44c97l9xiifbm-customClang/bin/customClang reported. This file is a dependency of every compilation action and
+that /nix/store/d6x389rgl2x9b6dkwxc71grbzgmkr28c-customClang/bin/customClang reported. This file is a dependency of every compilation action and
 changes to it will be reflected in the action cache key. When some of these
 paths change, Bazel will make sure to rerun the action, even though none of
 declared action inputs or the action commandline changes.
 
-/nix/store/vqbgiwjvjbgypsfwgpdc78asxvx13lsm-clang-wrapper-18.1.5/resource-root/include
+/nix/store/5ark5p94q2nwni9rkq9zqnfsyfv9y50w-clang-wrapper-18.1.5/resource-root/include
 /nix/store/s3pvsv4as7mc8i2nwnk2hnsyi2qdj4bq-glibc-2.39-31-dev/include
-/nix/store/vqbgiwjvjbgypsfwgpdc78asxvx13lsm-clang-wrapper-18.1.5/resource-root/share
+/nix/store/5ark5p94q2nwni9rkq9zqnfsyfv9y50w-clang-wrapper-18.1.5/resource-root/share
 /nix/store/csml9b5w7z51yc7hxgd2ax4m6vj36iyq-libcxx-18.1.5-dev/include/c++/v1
 /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk

local-remote-execution/generated-cc/cc/cc_wrapper.sh

@@ -22,4 +22,4 @@ set -eu
 
 
 # Call the C++ compiler
-/nix/store/6fr9bp9drswk1azlcby44c97l9xiifbm-customClang/bin/customClang "$@"
+/nix/store/d6x389rgl2x9b6dkwxc71grbzgmkr28c-customClang/bin/customClang "$@"