urbanterror: fix `configurePhase` phase

Use `preConfigure` and external file instead.

pkgs/games/urbanterror/Makefile.local

···
+USE_CURL = 1
+USE_CURL_DLOPEN = 0
+USE_FREETYPE = 1
+USE_OPENAL = 1
+USE_OPENAL_DLOPEN = 0

pkgs/games/urbanterror/default.nix

···
     SDL
   ];
 
-  configurePhase = ''
-    runHook preConfigure
-
-    echo "USE_OPENAL = 1" > Makefile.local
-    echo "USE_OPENAL_DLOPEN = 0" >> Makefile.local
-    echo "USE_CURL = 1" >> Makefile.local
-    echo "USE_CURL_DLOPEN = 0" >> Makefile.local
-
-    runHook postConfigure
+  preConfigure = ''
+    cp ${./Makefile.local} ./Makefile.local
   '';
 
   installTargets = [ "copyfiles" ];