diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index 230ee470..068124a7 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -54,7 +54,7 @@ jobs:
           ${{matrix.platform.msys-env}}-zlib
 
     - name: Configure CMake
-      run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{matrix.build-type}} -DBUILD_STATIC=${{matrix.build-static}} -DBUILD_TESTING=ON -DCMAKE_C_FLAGS="-Wall"
+      run: cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=${{matrix.build-type}} -DBUILD_STATIC=${{matrix.build-static}} -DBUILD_TESTING=ON -DCMAKE_C_FLAGS="-Wall -Werror"
 
     - name: Build
       run: cmake --build build
diff --git a/src/unshield.c b/src/unshield.c
index 9e0f8099..6f2a3dbd 100644
--- a/src/unshield.c
+++ b/src/unshield.c
@@ -510,9 +510,12 @@ static bool extract_file(Unshield* unshield, const char* prefix, int index)
 #endif
 
 #ifdef __GLIBC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-result"
   /* use GNU extension to return non-existing files to real_output_directory */
   realpath(output_directory, real_output_directory);
   realpath(filename, real_filename);
+#pragma GCC diagnostic pop
   if (real_filename == NULL || strncmp(real_filename,
                                        real_output_directory,
                                        strlen(real_output_directory)) != 0)