fix(ci): install libstdc++/libgcc for Alpine smoke test and add musl to PR matrix (#765)

## Summary

Fixes the `Build Binary (linux-x64-musl)` failure on main introduced by
#762.

Bun's musl binaries dynamically link `libstdc++` and `libgcc_s`, which
aren't included in bare `alpine:latest`. The smoke test now installs
these before running the binary.

Also adds `linux-x64-musl` to the PR build matrix so musl issues are
caught before merging.

Author: BYK

.github/workflows/ci.yml

@@ -66,9 +66,10 @@ jobs:
           {
             echo 'matrix<<MATRIX_EOF'
             if [[ "${{ github.event_name }}" == "pull_request" ]]; then
-              # PRs only need linux-x64 for smoke test and e2e — skip macOS/Windows
+              # PRs build linux-x64 (smoke test + e2e) and linux-x64-musl (Alpine smoke test)
               echo '{"include":[
-                {"target":"linux-x64", "os":"ubuntu-latest", "can-test":true}
+                {"target":"linux-x64",      "os":"ubuntu-latest", "can-test":true},
+                {"target":"linux-x64-musl", "os":"ubuntu-latest", "can-test":false}
               ]}'
             else
               # main, release/**, workflow_call: full cross-platform matrix
@@ -271,7 +272,7 @@ jobs:
         if: matrix.target == 'linux-x64-musl'
         run: |
           docker run --rm -v "$PWD/dist-bin:/dist-bin:ro" alpine:latest \
-            /dist-bin/sentry-linux-x64-musl --help
+            sh -c "apk add --no-cache libstdc++ libgcc >/dev/null 2>&1 && /dist-bin/sentry-linux-x64-musl --help"
       - name: Upload binary artifact
         uses: actions/upload-artifact@v7
         with:

install

@@ -167,6 +167,23 @@ if [[ "$os" == "linux" ]]; then
   if detect_musl; then
     libc_suffix="-musl"
     libc_variant="musl"
+
+    # Bun musl binaries dynamically link libstdc++ and libgcc_s.
+    # Auto-install them on Alpine when running as root (typical in Docker).
+    # When not root, warn with install instructions.
+    if ! ldconfig -p 2>/dev/null | grep -q libstdc++ && ! [ -f /usr/lib/libstdc++.so.6 ]; then
+      if command -v apk >/dev/null 2>&1; then
+        if [ "$(id -u)" = "0" ]; then
+          echo -e "${MUTED}Installing required C++ runtime libraries...${NC}"
+          apk add --no-cache libstdc++ libgcc >/dev/null 2>&1 \
+            || die "Failed to install libstdc++ and libgcc (required for musl binary)" "deps"
+        else
+          echo -e "${RED}Missing required libraries: libstdc++ libgcc${NC}" >&2
+          echo -e "${RED}Run: apk add libstdc++ libgcc${NC}" >&2
+          die "Cannot install dependencies without root. Run as root or install manually." "deps"
+        fi
+      fi
+    fi
   fi
 fi