Fix sysroot for cross-compilation

Issues fixed:
1. Sysroot hosted on GitHub releases but repo is private, causing 404s
2. Sysroot missing GCC directories that clang needs to find libstdc++ headers

Changes:
- Add GCC installation directories to sysroot (clang uses these to locate C++ headers)
- Update workflow to upload sysroot to DO Spaces instead of GitHub releases
- Versioned sysroot paths (v2, v3, etc.) for easier updates

NOTE: After merging, run the "Build Linux Sysroot" workflow with version "v2",
then update MODULE.bazel with the sha256 from the workflow output.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/build_sysroot.yml

@@ -3,14 +3,14 @@ name: Build Linux Sysroot
 on:
   workflow_dispatch:
     inputs:
-      create_release:
-        description: 'Create a GitHub release with the sysroot'
+      version:
+        description: 'Sysroot version (e.g., v2, v3)'
         required: true
-        default: 'true'
-        type: boolean
+        default: 'v2'
+        type: string
 
 permissions:
-  contents: write
+  contents: read
 
 jobs:
   build-sysroot:
@@ -28,23 +28,36 @@ jobs:
           name: ubuntu-noble-sysroot
           path: tools/sysroot/output/
 
-      - name: Create Release
-        if: ${{ inputs.create_release }}
-        uses: softprops/action-gh-release@v1
-        with:
-          tag_name: sysroot-noble-v1
-          name: Ubuntu 24.04 Noble Sysroot
-          body: |
-            Ubuntu 24.04 (Noble) sysroot for cross-compilation from macOS to Linux.
+      - name: Install AWS CLI
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y awscli
 
-            Contains:
-            - libstdc++-13 (C++23 support)
-            - libc6-dev
-            - linux-libc-dev
-            - zlib1g-dev
-            - libssl-dev
+      - name: Upload to DigitalOcean Spaces
+        env:
+          AWS_ACCESS_KEY_ID: ${{ secrets.ACCESS_KEY_ID }}
+          AWS_SECRET_ACCESS_KEY: ${{ secrets.SECRET_KEY }}
+        run: |
+          # Upload sysroot tarball to DO Spaces
+          aws s3 cp tools/sysroot/output/ubuntu_noble_amd64_sysroot.tar.xz \
+            s3://eagle0/sysroot/${{ inputs.version }}/ubuntu_noble_amd64_sysroot.tar.xz \
+            --endpoint-url https://sfo3.digitaloceanspaces.com \
+            --acl public-read
 
-            Use with toolchains_llvm sysroot rule.
-          files: |
-            tools/sysroot/output/ubuntu_noble_amd64_sysroot.tar.xz
-            tools/sysroot/output/ubuntu_noble_amd64_sysroot.sha256
+          # Upload sha256 file
+          aws s3 cp tools/sysroot/output/ubuntu_noble_amd64_sysroot.sha256 \
+            s3://eagle0/sysroot/${{ inputs.version }}/ubuntu_noble_amd64_sysroot.sha256 \
+            --endpoint-url https://sfo3.digitaloceanspaces.com \
+            --acl public-read
+
+          echo ""
+          echo "=== Sysroot uploaded ==="
+          echo "URL: https://eagle0.sfo3.digitaloceanspaces.com/sysroot/${{ inputs.version }}/ubuntu_noble_amd64_sysroot.tar.xz"
+          echo "SHA256: $(cat tools/sysroot/output/ubuntu_noble_amd64_sysroot.sha256)"
+          echo ""
+          echo "Update MODULE.bazel with:"
+          echo "sysroot("
+          echo "    name = \"linux_sysroot\","
+          echo "    sha256 = \"$(cat tools/sysroot/output/ubuntu_noble_amd64_sysroot.sha256)\","
+          echo "    urls = [\"https://eagle0.sfo3.digitaloceanspaces.com/sysroot/${{ inputs.version }}/ubuntu_noble_amd64_sysroot.tar.xz\"],"
+          echo ")"

MODULE.bazel

@@ -68,12 +68,13 @@ use_repo(llvm, "llvm_toolchain", "llvm_toolchain_linux")
 
 # Download the Linux sysroot (Ubuntu 24.04 Noble for C++23 support)
 # Built by: .github/workflows/build_sysroot.yml
-# To rebuild: Run the "Build Linux Sysroot" workflow and update sha256
+# To rebuild: Run the "Build Linux Sysroot" workflow with a new version, then update sha256 and URL
 sysroot = use_repo_rule("@toolchains_llvm//toolchain:sysroot.bzl", "sysroot")
 sysroot(
     name = "linux_sysroot",
-    sha256 = "3812d376beba78a301eb64dfe2ad01d5896500826054ebb6aa4e00607fa0e347",
-    urls = ["https://github.com/nolen777/eagle0/releases/download/sysroot-noble-v1/ubuntu_noble_amd64_sysroot.tar.xz"],
+    # TODO: Update sha256 after running sysroot build workflow with version v2
+    sha256 = "PLACEHOLDER_RUN_SYSROOT_WORKFLOW_FIRST",
+    urls = ["https://eagle0.sfo3.digitaloceanspaces.com/sysroot/v2/ubuntu_noble_amd64_sysroot.tar.xz"],
 )
 
 #

tools/sysroot/Dockerfile

@@ -2,6 +2,9 @@
 #
 # This creates a minimal sysroot containing headers and libraries needed
 # to cross-compile C++ code targeting Linux x86_64.
+#
+# Key requirement: Clang needs to find GCC's installation to locate libstdc++
+# headers. It looks for /usr/lib/gcc/<triple>/<version>/ in the sysroot.
 
 FROM ubuntu:24.04
 
@@ -10,6 +13,9 @@ FROM ubuntu:24.04
 RUN apt-get update && apt-get install -y --no-install-recommends \
     # C++ standard library with C++23 support (GCC 13)
     libstdc++-13-dev \
+    # GCC 13 (needed for Clang to find C++ headers via GCC detection)
+    gcc-13 \
+    g++-13 \
     # C library
     libc6-dev \
     # Linux kernel headers
@@ -20,11 +26,15 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     # Clean up
     && rm -rf /var/lib/apt/lists/*
 
-# Create a script to extract the sysroot
+# Create sysroot directory
 RUN mkdir -p /sysroot
 
 # Copy the essential directories for cross-compilation
+# Note: We preserve the exact directory structure that clang expects
 RUN cp -a /usr/include /sysroot/ && \
     cp -a /usr/lib/x86_64-linux-gnu /sysroot/usr_lib && \
     mkdir -p /sysroot/lib && \
-    cp -a /lib/x86_64-linux-gnu /sysroot/lib/
+    cp -a /lib/x86_64-linux-gnu /sysroot/lib/ && \
+    # Copy GCC installation directory - Clang uses this to find libstdc++ headers
+    mkdir -p /sysroot/usr/lib/gcc && \
+    cp -a /usr/lib/gcc/x86_64-linux-gnu /sysroot/usr/lib/gcc/

tools/sysroot/build_sysroot.sh

@@ -39,6 +39,10 @@ docker cp "${CONTAINER_ID}:/sysroot/include" "${SYSROOT_DIR}/usr/"
 docker cp "${CONTAINER_ID}:/sysroot/usr_lib" "${SYSROOT_DIR}/usr/lib/x86_64-linux-gnu"
 docker cp "${CONTAINER_ID}:/sysroot/lib/x86_64-linux-gnu" "${SYSROOT_DIR}/lib/"
 
+# Copy GCC installation directory - Clang uses this to find libstdc++ headers
+# The path /usr/lib/gcc/x86_64-linux-gnu/13 is where clang looks for GCC
+docker cp "${CONTAINER_ID}:/sysroot/usr/lib/gcc" "${SYSROOT_DIR}/usr/lib/"
+
 # Also need lib64 symlink for some builds
 ln -sf lib "${SYSROOT_DIR}/lib64"