Add buildtools+setupenv+configure workflow

Author: Numerio

.github/workflows/buildtools-build.yml

@@ -0,0 +1,69 @@
+name: buildtools build
+on:
+  push:
+    branches:
+      - '**'
+
+jobs:
+  buildtools:
+    name: Build buildtools + configure
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Install build dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y --no-install-recommends \
+            bison build-essential cmake debootstrap debhelper \
+            dh-dkms dkms elfutils flex git \
+            grub-efi-amd64-bin grub-pc-bin \
+            libdrm-dev libelf-dev libfl-dev libfreetype6-dev \
+            libgif-dev libicns-dev libicu-dev libinput-dev \
+            libjpeg-dev libncurses-dev libopenexr-dev libpng-dev \
+            libtiff-dev libudev-dev libwebp-dev \
+            linux-headers-$(uname -r) \
+            mtools ninja-build squashfs-tools sudo xorriso zlib1g-dev \
+            fakeroot devscripts lintian wget
+
+      - name: Configure git safe.directory
+        run: git config --global --add safe.directory $GITHUB_WORKSPACE
+
+      - name: Init submodules
+        run: git submodule update --init --recursive
+
+      - name: Create buildtools directory
+        run: mkdir -p buildtools
+
+      - name: Build buildtools (cmake + ninja configure)
+        run: |
+          cd buildtools
+          cmake -DBUILDTOOLS_MODE=1 .. -GNinja
+          ninja -v -t clean || true
+          # Do not run the actual ninja build; only configure step completed.
+
+      - name: Create build directory
+        run: mkdir -p generated.x86
+
+      - name: Setup environment
+        run: |
+          cd generated.x86
+          export TERM=xterm-256color
+          ../build/scripts/setupenv.sh
+
+      - name: Configure project
+        run: |
+          cd generated.x86
+          BUILD_TYPE=Workflow ../configure
+
+      - name: Archive intermediate state
+        uses: actions/upload-artifact@v4
+        with:
+          name: buildtools-stage
+          path: |
+            buildtools/**
+            generated.x86/**