Stop on warnings for CI

.github/workflows/ccpp.yml

@@ -12,10 +12,10 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - name: make check C99
-      run: make check
+      run: make clean check CC="cc -std=c99 -Wno-unknown-warning-option -Werror"
     - name: make check C11
       working-directory: ./tests
-      run: make clean check CC="cc -std=c11"
+      run: make clean check CC="cc -std=c11 -Wno-unknown-warning-option -Werror"
     - name: make check C++
       working-directory: ./tests
       run: make clean check CC="c++ -std=c++11"
@@ -27,12 +27,12 @@ jobs:
     - uses: actions/checkout@v1
     - name: install multilib
       run: sudo apt-get install gcc-multilib
-    - name: make check C99
+    - name: make check C99 (32bits)
       working-directory: ./tests
-      run: make clean check CC="gcc -m32 -std=c99"
-    - name: make check C11
+      run: make clean check CC="gcc -m32 -std=c99 -Wno-unknown-warning-option -Werror"
+    - name: make check C11 (32bits)
       working-directory: ./tests
-      run: make clean check CC="gcc -m32 -std=c11"
+      run: make clean check CC="gcc -m32 -std=c11 -Wno-unknown-warning-option -Werror"
  
   build_linux_tcc:
     runs-on: ubuntu-latest