maude: try what happens when we re-enable parallel building

Tests look good, maybe the build issue that broke this a while
ago has been fixed?

pkgs/development/interpreters/maude/default.nix

@@ -55,10 +55,7 @@ stdenv.mkDerivation {
     install -D -m 444 full-maude.maude $out/share/maude/full-maude.maude
   '';
 
-  # bison -dv surface.yy -o surface.c
-  # mv surface.c surface.cc
-  # mv: cannot stat 'surface.c': No such file or directory
-  enableParallelBuilding = false;
+  enableParallelBuilding = true;
 
   meta = {
     broken = stdenv.isDarwin;