CI + native Debian

.gitlab-ci.yml

 stages:
   - build
+
+native_Debian_clang:
+  tags:
+  - Debian
+  stage: build
+  before_script: &debian_clang
+    - export CC=clang; export CXX=clang++
+    - cmake --version
+    - clang --version
+  script:
+    - mkdir build
+    - cd build
+    - cmake -DWERROR=ON ..
+    - make
+    - ctest --output-on-failure
+#    - cpack .
+  artifacts:
+    paths:
+    - build/*zip
+    expire_in: 10 days
+
 mac:
   tags:
   - MacOS
@@ -16,6 +37,29 @@ mac:
     - build/*zip
     expire_in: 10 days
 
+windows:
+  tags:
+  - Windows
+  stage: build
+  script:
+    - New-Item -ItemType "directory" -Confirm:$false -Force:$true -Name "build"
+    - cd build
+    # We want to compile with Mingw-w64. Somehow this is accomplished by Ninja.
+    - cmake -G "Ninja" -DLIB_MAN=OFF -DCMAKE_INSTALL_PREFIX=C:\opt\x64 -B. ..
+    - cmake --build . # --config Release
+    - Get-Location
+    - dir
+    - ctest --output-on-failure # -C Release
+    - cmake --install .
+  artifacts:
+    paths:
+    - lib/kww.h
+    - build/lib/libkww.dll
+    - build/demo/runkww.exe
+    expire_in: 10 days
+
+## dockerized:
+
 debS_clang:
   tags: &unix
   - Linux
@@ -142,24 +186,3 @@ centos7_gcc:
     - ln -s /usr/bin/cpack3 /usr/bin/cpack
   stage: build
   script: *scr
-
-windows:
-  tags:
-  - Windows
-  stage: build
-  script:
-    - New-Item -ItemType "directory" -Confirm:$false -Force:$true -Name "build"
-    - cd build
-    # We want to compile with Mingw-w64. Somehow this is accomplished by Ninja.
-    - cmake -G "Ninja" -DLIB_MAN=OFF -DCMAKE_INSTALL_PREFIX=C:\opt\x64 -B. ..
-    - cmake --build . # --config Release
-    - Get-Location
-    - dir
-    - ctest --output-on-failure # -C Release
-    - cmake --install .
-  artifacts:
-    paths:
-    - lib/kww.h
-    - build/lib/libkww.dll
-    - build/demo/runkww.exe
-    expire_in: 10 days