[CI] GitHub Actions: install gettext

Author: Rechi

.github/workflows/build.yml

@@ -17,6 +17,10 @@ jobs:
             CC: clang
             CXX: clang++
     steps:
+    - name: Install gettext
+      run: |
+        sudo apt-get update -qq
+        sudo apt-get install -y gettext
     - name: Checkout Kodi repo
       uses: actions/checkout@v5
       with: