ppsspp: fix up

pkgs/misc/emulators/ppsspp/default.nix

@@ -5,7 +5,7 @@ assert withGamepads -> (SDL2 != null);
 with stdenv.lib;
 
 stdenv.mkDerivation rec {
-  name = "PPSSPP-${version}";
+  name = "ppsspp-${version}";
   version = "1.4.2";
 
   src = fetchFromGitHub {
@@ -33,6 +33,8 @@ stdenv.mkDerivation rec {
     mv assets $out/share/ppsspp
   '';
 
+  enableParallelBuilding = true;
+
   meta = {
     homepage = https://www.ppsspp.org/;
     description = "A PSP emulator for Android, Windows, Mac and Linux, written in C++";