DXFILMEDGE: suppress gcc warning -Wmaybe-uninitialized

CMakeFile: don't disable -fno-var-tracking-assignments for gcc
github: try installing de_DE.UTF-8 locale (for test_filemem)

.github/workflows/ci.yml

@@ -24,6 +24,10 @@ jobs:
     - name: Install libpng-dev
       run: sudo apt-get install libpng-dev
 
+    - name: Install locale
+      shell: bash
+      run: sudo locale-gen de_DE.UTF-8 && sudo update-locale
+
     - name: Create Build Environment
       # Some projects don't allow in-source building, so create a separate build directory
       # We'll use this as our working directory for all subsequent commands