ci: turn on werror

.github/workflows/main.yml

@@ -24,10 +24,10 @@ jobs:
       - name: Build with gcc
         run: |
           export CC=gcc CXX=g++
-          meson build-gcc/
+          meson build-gcc/ --werror=true
           ninja -C build-gcc/
       - name: Build with clang
         run: |
           export CC=clang CXX=clang++
-          meson build-clang/
+          meson build-clang/ --werror=true
           ninja -C build-clang/

meson.build

@@ -18,6 +18,7 @@ cppc = meson.get_compiler('cpp')
 add_project_arguments(cppc.get_supported_arguments([
   '-Wno-unused-parameter',
   '-Wno-missing-field-initializers',
+  '-Wno-c99-designator'
 ]), language: 'cpp')
 
 dep_x11 = dependency('x11')