fix(linux-build): install patch utility and try GCC 11 for Electron header compat

Two fixes for the 'fatal error: source_location: No such file or directory'
failure in native-keymap compilation on focal-* containers:

1. deps.sh: install the `patch` utility. preinstall.ts calls `patch` to
   apply v8-source-location.patch to downloaded Electron headers, but the
   focal Docker images don't ship `patch` by default — causing execFileSync
   to throw ENOENT and silently skip the patch.

2. package_bin.sh: try apt-get install g++-11 before falling back to g++-10.
   GCC 11 ships with <source_location> natively (C++20), avoiding the need
   for the header patch entirely on containers where GCC 11 is available.
   Also set VSCODE_FORCE_INSTALL=1 to ensure preinstall.ts always runs
   installHeaders() even if a stale state hash is somehow present.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Tajudeen

build/linux/deps.sh

@@ -4,7 +4,8 @@ set -ex
 
 sudo apt-get update -y
 
-sudo apt-get install -y libkrb5-dev
+# patch is required by preinstall.ts to apply v8-source-location.patch to Electron headers
+sudo apt-get install -y libkrb5-dev patch
 
 if [[ "${VSCODE_ARCH}" == "arm64" ]]; then
   sudo apt-get install -y gcc-aarch64-linux-gnu g++-aarch64-linux-gnu crossbuild-essential-arm64

build/linux/package_bin.sh

@@ -174,20 +174,20 @@ if [[ -z "${VSCODE_SKIP_SETUPENV}" ]]; then
   fi
 fi
 
-# Node.js 22 C++ headers require GCC 10+ (<source_location> C++20 header).
-# focal containers ship with GCC 9 by default; upgrade if possible.
-if ! command -v g++-10 &>/dev/null && ! command -v g++-11 &>/dev/null; then
-  echo "GCC 10+ not found — attempting apt-get install g++-10..."
-  apt-get install -yq g++-10 gcc-10 2>/dev/null || echo "Warning: apt-get install g++-10 failed"
+# Electron 39+ headers require <source_location> (C++20, GCC 11+).
+# focal containers ship with GCC 9/10 by default; try GCC 11 first, then 10.
+if ! command -v g++-11 &>/dev/null; then
+  echo "GCC 11 not found — attempting apt-get install g++-11..."
+  apt-get install -yq g++-11 gcc-11 2>/dev/null || echo "Warning: apt-get install g++-11 failed"
 fi
-if command -v g++-10 &>/dev/null; then
-  export CXX=g++-10 CC=gcc-10
-  echo "Using GCC 10 for native module compilation"
-elif command -v g++-11 &>/dev/null; then
+if command -v g++-11 &>/dev/null; then
   export CXX=g++-11 CC=gcc-11
   echo "Using GCC 11 for native module compilation"
+elif command -v g++-10 &>/dev/null; then
+  export CXX=g++-10 CC=gcc-10
+  echo "Using GCC 10 for native module compilation"
 else
-  echo "Warning: GCC 10+ not available; native-keymap may fail to compile with Node.js 22 headers"
+  echo "Warning: GCC 11/10 not available; native module compilation may fail"
 fi
 
 # For alternative architectures, skip postinstall scripts to avoid unsupported platform errors
@@ -197,6 +197,12 @@ if [[ "${VSCODE_ARCH}" == "riscv64" ]] || [[ "${VSCODE_ARCH}" == "ppc64le" ]] ||
   echo "Skipping postinstall scripts for ${VSCODE_ARCH} (unsupported by some packages)"
 fi
 
+# Force preinstall.ts to run fully (bypass isUpToDate state-hash check).
+# The compile-step artifact doesn't include node_modules/.postinstall-state,
+# so preinstall normally re-runs anyway — but VSCODE_FORCE_INSTALL=1 makes
+# this explicit and ensures installHeaders() is called on every packaging run.
+export VSCODE_FORCE_INSTALL=1
+
 for i in {1..5}; do # try 5 times
   npm ci ${NPM_CI_OPTS} && break
   if [[ $i -eq 5 ]]; then