ci: Introduce artifacts

Separates `test-linux` into `build-linux` and `test-linux`, wherein `build-` builds out of tree, and uploading the build for the `test-` job.
Tar compression is done to retain execution permissions when downloading build artifact.
When calling `make test`, override `TARGETS` and `EXTRA_TARGETS` to prevent rebuild.

.github/workflows/test-linux.yml

@@ -1,6 +1,12 @@
 name: Build and run tests (Linux)
 
-on: [push, pull_request]
+on:
+  pull_request:
+    branches:
+    - master
+  push:
+    branches:
+    - master
 
 jobs:
   pre_job:
@@ -17,7 +23,7 @@ jobs:
           # only run on push *or* pull_request, not both
           concurrent_skipping: 'same_content_newer'
 
-  test-linux:
+  build-linux:
     needs: pre_job
     if: needs.pre_job.outputs.should_skip != 'true'
     runs-on: ${{ matrix.os.id }}
@@ -123,25 +129,61 @@ jobs:
           make -j${{ env.procs }}
           make install
 
-      - name: Build yosys
+      - name: Build yosys out-of-tree
         shell: bash
         run: |
-          make config-${CC%%-*}
-          make -j${{ env.procs }} CXXSTD=${{ matrix.cpp_std }} CC=$CC CXX=$CC LD=$CC
+          mkdir build
+          cd build
+          make -f ../Makefile config-${CC%%-*}
+          make -f ../Makefile -j${{ env.procs }} CXXSTD=${{ matrix.cpp_std }} CC=$CC CXX=$CC LD=$CC
+
+      - name: Log yosys-config output
+        run: |
+          ./yosys-config || true
+
+      - name: Compress build
+        shell: bash
+        run: |
+          cd build
+          tar -cvf ../build.tar Makefile.conf share/ yosys yosys-*
 
       - name: Store build artifact
         if: (matrix.cpp_std == 'c++11') && (matrix.compiler == 'gcc-11')
         uses: actions/upload-artifact@v4
         with:
-          name: compiled-yosys
-          path: yosys
+          name: build-artifact
+          path: build.tar
+          retention-days: 1
 
-      - name: Run tests
-        if: (matrix.cpp_std == 'c++11') && (matrix.compiler == 'gcc-11')
+  test-linux:
+    name: Run tests
+    needs: build-linux
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Dependencies
         shell: bash
         run: |
-          make -j${{ env.procs }} test CXXSTD=${{ matrix.cpp_std }} CC=$CC CXX=$CC LD=$CC
+          sudo apt-get update
+          sudo apt-get install gperf build-essential bison flex libreadline-dev gawk tcl-dev libffi-dev git graphviz xdot pkg-config python3 libboost-system-dev libboost-python-dev libboost-filesystem-dev zlib1g-dev
 
-      - name: Log yosys-config output
+      - name: Runtime environment
+        shell: bash
+        env:
+          WORKSPACE: ${{ github.workspace }}
         run: |
-          ./yosys-config || true
+          echo "procs=$(nproc)" >> $GITHUB_ENV
+
+      - name: Download build artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: build-artifact
+
+      - name: Uncompress build
+        shell: bash
+        run:
+          tar -xvf build.tar
+
+      - name: Run tests
+        shell: bash
+        run: |
+          make -j${{ env.procs }} test TARGETS= EXTRA_TARGETS=