flite: 1.9.0 -> 2.0.0, fix build with Nix 1.12

It is failing with:

     RPATH of binary /nix/store/...-flite-.../bin/flite contains a forbidden reference to /build

because of the rpath entry `../build/x86_64-linux-gnu/lib`.

pkgs/development/libraries/flite/default.nix

@@ -1,18 +1,18 @@
-{ stdenv, fetchurl, pkgconfig }:
+{ stdenv, fetchurl }:
 
 stdenv.mkDerivation rec {
-  name = "flite-1.9.0";
+  name = "flite-2.0.0";
 
   src = fetchurl {
-    url = "http://www.festvox.org/bard/${name}-current.tar.bz2";
-    sha256 = "197cc2a1f045b1666a29a9b5f035b3d676db6db94a4439d99a03b65e551ae2e0";
+    url = "http://www.festvox.org/flite/packed/flite-2.0/${name}-release.tar.bz2";
+    sha256 = "04g4r83jh4cl0irc8bg7njngcah7749956v9s6sh552kzmh3i337";
   };
 
-  nativeBuildInputs = [ pkgconfig ];
+  patches = [ ./fix-rpath.patch ];
 
-  configureFlags = ''
-    --enable-shared
-  '';
+  configureFlags = [ "--enable-shared" ];
+
+  enableParallelBuilding = true;
 
   meta = {
     description = "A small, fast run-time speech synthesis engine";

pkgs/development/libraries/flite/fix-rpath.patch

@@ -0,0 +1,5 @@
+--- a/main/Makefile
++++ b/main/Makefile
+@@ -81 +80,1 @@ ifdef SHFLAGS
+-flite_LIBS_flags += -Wl,-rpath $(LIBDIR) 
++flite_LIBS_flags += -Wl,-rpath,$(INSTALLLIBDIR)