ci: Use BuildJet Ubuntu 20.04 runners for better glibc compatibility (#18442)

Use BuildJet Ubuntu 20.04 runners.
- Linux arm64 unchanged (glibc >= 2.35)
- Linux x64 glibc requirement becomes to >= 2.31 (from glibc >= 2.35).

Note: Ubuntu 20.04 repo cmake (3.16.3) is normally too old to build Zed, but `ubuntu-2004` [includes cmake
3.30.3](https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2004-Readme.md#tools).

.github/workflows/ci.yml

@@ -254,7 +254,7 @@ jobs:
     timeout-minutes: 60
     name: Create a Linux bundle
     runs-on:
-      - buildjet-16vcpu-ubuntu-2204
+      - buildjet-16vcpu-ubuntu-2004
     if: ${{ startsWith(github.ref, 'refs/tags/v') || contains(github.event.pull_request.labels.*.name, 'run-bundling') }}
     needs: [linux_tests]
     env:
@@ -267,7 +267,7 @@ jobs:
           clean: false
 
       - name: Install Linux dependencies
-        run: ./script/linux
+        run: ./script/linux && ./script/install-mold 2.34.0
 
       - name: Determine version and release channel
         if: ${{ startsWith(github.ref, 'refs/tags/v') }}

.github/workflows/release_nightly.yml

@@ -100,7 +100,7 @@ jobs:
     name: Create a Linux *.tar.gz bundle for x86
     if: github.repository_owner == 'zed-industries'
     runs-on:
-      - buildjet-16vcpu-ubuntu-2204
+      - buildjet-16vcpu-ubuntu-2004
     needs: tests
     env:
       DIGITALOCEAN_SPACES_ACCESS_KEY: ${{ secrets.DIGITALOCEAN_SPACES_ACCESS_KEY }}
@@ -117,7 +117,7 @@ jobs:
         run: echo "$HOME/.cargo/bin" >> $GITHUB_PATH
 
       - name: Install Linux dependencies
-        run: ./script/linux
+        run: ./script/linux && ./script/install-mold 2.34.0
 
       - name: Limit target directory size
         run: script/clear-target-dir-if-larger-than 100

docs/src/linux.md

@@ -16,7 +16,7 @@ The Zed installed by the script works best on systems that:
 
 - have a Vulkan compatible GPU available (for example Linux on an M-series macBook)
 - have a system-wide glibc (NixOS and Alpine do not by default)
-  - x86_64 (Intel/AMD): glibc version >= 2.35 (Ubuntu 22 and newer)
+  - x86_64 (Intel/AMD): glibc version >= 2.29 (Ubuntu 20 and newer)
   - aarch64 (ARM): glibc version >= 2.35 (Ubuntu 22 and newer)
 
 Both Nix and Alpine have third-party Zed packages available (though they are currently a few weeks out of date). If you'd like to use our builds they do work if you install a glibc compatibility layer. On NixOS you can try [nix-ld](https://github.com/Mic92/nix-ld), and on Alpine [gcompat](https://wiki.alpinelinux.org/wiki/Running_glibc_programs).
@@ -24,8 +24,8 @@ Both Nix and Alpine have third-party Zed packages available (though they are cur
 You will need to build from source for:
 
 - architectures other than 64-bit Intel or 64-bit ARM (for example a 32-bit or RISC-V machine)
-- Amazon Linux
-- Rocky Linux 9.3
+- Redhat Enterprise Linux 8.x, Rocky Linux 8, AlmaLinux 8, Amazon Linux 2 on all architectures
+- Redhat Enterprise Linux 9.x, Rocky Linux 9.3, AlmaLinux 8, Amazon Linux 2023 on aarch64 (x86_x64 OK)
 
 ## Other ways to install Zed on Linux
 

script/install-mold

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+
+# Install `mold` official binaries from GitHub Releases.
+#
+# Adapted from the official rui314/setup-mold@v1 action to:
+# * use environment variables instead of action inputs
+# * remove make-default support
+# * use curl instead of wget
+# * support doas for sudo
+# * support redhat systems
+# See: https://github.com/rui314/setup-mold/blob/main/action.yml
+
+set -euo pipefail
+
+MOLD_VERSION="${MOLD_VERSION:-${1:-}}"
+if [ "$(uname -s)" != "Linux" ]; then
+    echo "Error: This script is intended for Linux systems only."
+    exit 1
+elif [ -z "$MOLD_VERSION" ]; then
+    echo "Usage: $0 2.34.0"
+    exit 1
+elif [ -e /usr/local/bin/mold ]; then
+    echo "Warning: existing mold found at /usr/local/bin/mold. Skipping installation."
+    exit 0
+fi
+
+if [ "$(whoami)" = root ]; then SUDO=; else SUDO="$(command -v sudo || command -v doas || true)"; fi
+
+MOLD_REPO="${MOLD_REPO:-https://github.com/rui314/mold}"
+MOLD_URL="${MOLD_URL:-$MOLD_REPO}/releases/download/v$MOLD_VERSION/mold-$MOLD_VERSION-$(uname -m)-linux.tar.gz"
+
+echo "Downloading from $MOLD_URL"
+curl --location --show-error --output - --retry 3 --retry-delay 5 "$MOLD_URL" \
+    | $SUDO tar -C /usr/local --strip-components=1 --no-overwrite-dir -xzf -
+
+# Note this binary depends on the system libatomic.so.1 which is usually
+# provided as a dependency of gcc so it should be available on most systems.

script/linux

@@ -20,19 +20,29 @@ if [[ -n $apt ]]; then
     libwayland-dev
     libxkbcommon-x11-dev
     libssl-dev
-    libstdc++-12-dev
     libzstd-dev
     libvulkan1
     libgit2-dev
     make
     cmake
     clang
-    mold
     jq
     gettext-base
     elfutils
     libsqlite3-dev
   )
+  # Ubuntu 20.04 / Debian Bullseye (including CI for release)
+  if grep -q "bullseye" /etc/debian_version; then
+    deps+=(
+      libstdc++-10-dev
+    )
+  else
+    deps+=(
+      libstdc++-12-dev
+      mold
+    )
+  fi
+
   $maysudo "$apt" update
   $maysudo "$apt" install -y "${deps[@]}"
   exit 0