Fix LTO setting on Linux

.buildkite/scripts/env.sh

@@ -80,6 +80,9 @@ function export_environment() {
   export ZIG_LOCAL_CACHE_DIR="$HOME/.cache/zig-cache/$BUILDKITE_STEP_KEY"
   export ZIG_GLOBAL_CACHE_DIR="$HOME/.cache/zig-cache/$BUILDKITE_STEP_KEY"
   export BUN_DEPS_CACHE_DIR="$HOME/.cache/bun-deps/$BUILDKITE_STEP_KEY"
+  if [ "$(assert_os)" == "darwin" ]; then
+    export USE_LTO="ON"
+  fi
   if [ "$(assert_arch)" == "aarch64" ]; then
     export CPU_TARGET="native"
   elif [[ "$BUILDKITE_STEP_KEY" == *"baseline"* ]]; then

Dockerfile

@@ -52,7 +52,7 @@ ENV CI 1
 ENV CPU_TARGET=${CPU_TARGET}
 ENV BUILDARCH=${BUILDARCH}
 ENV BUN_DEPS_OUT_DIR=${BUN_DEPS_OUT_DIR}
-ENV BUN_ENABLE_LTO 1
+ENV USE_LTO 1
 
 ENV LC_CTYPE=en_US.UTF-8
 ENV LC_ALL=en_US.UTF-8

scripts/env.sh

@@ -60,7 +60,7 @@ export CXXFLAGS='-O3 -fno-exceptions -fno-rtti -fvisibility=hidden -fvisibility-
 
 # Add flags for LTO
 # We cannot enable LTO on macOS for dependencies because it requires -fuse-ld=lld and lld causes many segfaults on macOS (likely related to stack size)
-if [ "$BUN_ENABLE_LTO" == "1" ]; then
+if [ "$USE_LTO" == "1" ] || [ "$USE_LTO" == "ON" ]; then
   export CFLAGS="$CFLAGS -flto=full "
   export CXXFLAGS="$CXXFLAGS -flto=full -fwhole-program-vtables -fforce-emit-vtables "
   export LDFLAGS="$LDFLAGS -flto=full -fwhole-program-vtables -fforce-emit-vtables "