ci: set meson to build with -Werror

This will help catch any new warnings added in CI.

.github/workflows/test.yml

@@ -53,7 +53,7 @@ jobs:
 
       - name: Build
         run: |
-          meson _build
+          meson _build -Dwerror=true
           meson compile -C _build
 
       - name: Run tests
@@ -98,7 +98,7 @@ jobs:
 
       - name: Build
         run: |
-          meson _build
+          meson _build -Dwerror=true
           meson compile -C _build
 
       - name: Run tests

.woodpecker.yml

@@ -4,7 +4,7 @@ pipeline:
     commands:
       - apt-get update
       - apt-get install -y kyua atf-sh build-essential meson
-      - meson _build
+      - meson _build -Dwerror=true
       - meson compile -C _build
       - meson test -v -C _build
     when:
@@ -30,7 +30,7 @@ pipeline:
     image: alpine
     commands:
       - apk add -U --no-cache kyua atf build-base meson
-      - meson _build
+      - meson _build -Dwerror=true
       - meson compile -C _build
       - meson test -v -C _build
     when: