Update build.sh

Author: d10sfan

engines/warzone2100/build.sh

@@ -17,6 +17,7 @@ cmake \
     -DCMAKE_BUILD_TYPE=RelWithDebInfo \
     -DWZ_ENABLE_WARNINGS_AS_ERRORS=OFF \
     -DENABLE_DOCS=OFF \
+    -G Ninja \
     ..
 cmake --build . --target install
 popd