luarocks: upstream patch to fix make -j

Formula/luarocks.rb

@@ -12,7 +12,11 @@ class Luarocks < Formula
   fails_with_llvm "Lua itself compiles with llvm, but may fail when other software tries to link."
 
   def patches
-    DATA if HOMEBREW_PREFIX.to_s == '/usr/local'
+    p = []
+    p << DATA if HOMEBREW_PREFIX.to_s == '/usr/local'
+    # Allow parallel builds; will be in 2.0.9
+    p << "https://github.com/keplerproject/luarocks/commit/0431ed91571e4b7986a1178df48232abff7c0916.patch"
+    p
   end
 
   def options
@@ -32,7 +36,6 @@ class Luarocks < Formula
 
     system "./configure", *args
     system "make"
-    ENV.j1 # 2.0.4.1 worked in parallel but 2.0.7.1 does not
     system "make install"
   end