Makefile: don't build the sources in make check-source.

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index f566806a..8fb75e60 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -101,10 +101,6 @@ jobs:
           name: pytest-results-prebuild
           path: report.xml
           if-no-files-found: ignore
-      - name: Check Generated Files have been updated
-        run: uv run make check-gen-updated
-      - name: Check docs
-        run: uv run make check-doc
 
   compile:
     name: Compile CLN ${{ matrix.cfg }}
@@ -171,6 +167,41 @@ jobs:
           name: cln-${{ matrix.CFG }}.tar.bz2
           path: cln-${{ matrix.CFG }}.tar.bz2
 
+  check-compiled-source:
+    runs-on: ubuntu-24.04
+    needs:
+      - compile
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python 3.10
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+
+      - name: Install dependencies
+        run: |
+          bash -x .github/scripts/setup.sh
+
+      - name: Download build
+        uses: actions/download-artifact@v4
+        with:
+          name: cln-compile-gcc.tar.bz2
+
+      - name: Unpack pre-built CLN
+        env:
+          CFG: ${{ matrix.CFG }}
+        run: |
+          tar -xaf cln-compile-gcc.tar.bz2
+
+      - name: Check
+        run: |
+          uv run eatmydata make -j $(nproc) check-source-bolt check-python check-gen-updated check-doc
+
   check-units:
     # The unit test checks are not in the critical path (not dependent
     # on the integration tests), so run them with `valgrind`
@@ -765,11 +796,12 @@ jobs:
       - integration-sanitizers
       - min-btc-support
       - check-downgrade
+      - check-compiled-source
     if: ${{ always() }}
     steps:
       - name: Complete
         env:
-          JOB_NAMES: "INTEGRATION CHECK_UNITS VALGRIND SANITIZERS BTC"
+          JOB_NAMES: "INTEGRATION CHECK_UNITS VALGRIND SANITIZERS BTC CHECK_COMPILED_SOURCE"
           INTEGRATION: ${{ needs.integration.result }}
           CHECK_UNITS: ${{ needs['check-units'].result }}
           VALGRIND: ${{ needs['integration-valgrind'].result }}
@@ -777,6 +809,7 @@ jobs:
           DOCS: ${{ needs['update-docs-examples'].result }}
           BTC: ${{ needs['min-btc-support'].result }}
           CHECK_DOWNGRADE: ${{ needs['check-downgrade'].result }}
+          CHECK_COMPILED_SOURCE: ${{ needs['check-compiled-source'].result }}
         run: |
           failed=""
           for name in $JOB_NAMES; do
diff --git a/Makefile b/Makefile
index e59e9f0b..7f7e9d97 100644
--- a/Makefile
+++ b/Makefile
@@ -649,10 +649,8 @@ update-doc-examples:
 check-doc-examples: update-doc-examples
 	git diff --exit-code HEAD
 
-# For those without working cppcheck
-check-source-no-cppcheck: check-makefile check-source-bolt check-whitespace check-spelling check-python check-includes check-shellcheck check-setup_locale check-tmpctx check-discouraged-functions check-amount-access check-bad-sprintf
-
-check-source: check-source-no-cppcheck
+# This should NOT compile things!
+check-source: check-makefile check-whitespace check-spelling check-python-flake8 check-includes check-shellcheck check-setup_locale check-tmpctx check-discouraged-functions check-amount-access check-bad-sprintf
 
 full-check: check check-source
 
diff --git a/common/Makefile b/common/Makefile
index 41926116..62ceb252 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -157,8 +157,8 @@ ALL_C_SOURCES += $(COMMON_SRC)
 common/htlc_state_names_gen.h: common/htlc_state.h ccan/ccan/cdump/tools/cdump-enumstr
 	ccan/ccan/cdump/tools/cdump-enumstr common/htlc_state.h > $@
 
-check-source-bolt: $(COMMON_SRC_NOGEN:%=bolt-check/%) $(COMMON_HEADERS:%=bolt-check/%)
-check-whitespace: $(COMMON_SRC_NOGEN:%=check-whitespace/%) $(COMMON_HEADERS:%=check-whitespace/%)
+check-source-bolt: $(COMMON_SRC_NOGEN:%=bolt-check/%) $(COMMON_HEADERS_NOGEN:%=bolt-check/%)
+check-whitespace: $(COMMON_SRC_NOGEN:%=check-whitespace/%) $(COMMON_HEADERS_NOGEN:%=check-whitespace/%)
 
 clean: common-clean