llvm: update 3.3 -> 3.4

- Drop a patch that no longer applies: the default limit got tripled,
  so I hope it's sufficient now anyway.
- R600 support is no longer experimental and enabled by default.
- A few packages haven't been ported to 3.4 by upstream yet,
  so I will probably re-introduce 3.3 for them
  (so we can merge to master sooner).

pkgs/development/compilers/llvm/default.nix

@@ -1,18 +1,15 @@
 { stdenv, fetchurl, perl, groff, cmake, python, libffi, binutils_gold }:
 
-let version = "3.3"; in
+let version = "3.4"; in
 
 stdenv.mkDerivation rec {
   name = "llvm-${version}";
 
   src = fetchurl {
     url    = "http://llvm.org/releases/${version}/llvm-${version}.src.tar.gz";
-    sha256 = "0y3mfbb5qzcpw3v5qncn69x1hdrrrfirgs82ypi2annhf0g6nxk8";
+    sha256 = "0a169ba045r4apb9cv6ncrwl83l7yiajnzirkcdlhj1cd4nn3995";
   };
 
-  # The default rlimits are too low for shared libraries.
-  patches = [ ./more-memory-for-bugpoint.patch ];
-
   # libffi was propagated before, but it wasn't even being used, so
   # unless something needs it just an input is fine.
   buildInputs = [ perl groff cmake python libffi ]; # ToDo: polly, libc++; enable cxx11?
@@ -25,7 +22,6 @@ stdenv.mkDerivation rec {
     "-DCMAKE_BUILD_TYPE=Release"
     "-DLLVM_ENABLE_FFI=ON"
     "-DLLVM_BINUTILS_INCDIR=${binutils_gold}/include"
-    "-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=R600" # for mesa
   ] ++ lib.optional (!isDarwin) "-DBUILD_SHARED_LIBS=ON";
 
   enableParallelBuilding = true;

pkgs/development/compilers/llvm/more-memory-for-bugpoint.patch

@@ -1,15 +0,0 @@
-diff -Naur llvm-3.3.src-orig/tools/bugpoint/bugpoint.cpp llvm-3.3.src/tools/bugpoint/bugpoint.cpp
---- llvm-3.3.src-orig/tools/bugpoint/bugpoint.cpp	2013-01-27 20:35:51.000000000 -0500
-+++ llvm-3.3.src/tools/bugpoint/bugpoint.cpp	2013-06-21 18:29:47.612731499 -0400
-@@ -48,9 +48,9 @@
-                       "is killed (default is 300s), 0 disables timeout"));
- 
- static cl::opt<int>
--MemoryLimit("mlimit", cl::init(-1), cl::value_desc("MBytes"),
-+MemoryLimit("mlimit", cl::init(0), cl::value_desc("MBytes"),
-              cl::desc("Maximum amount of memory to use. 0 disables check."
--                      " Defaults to 100MB (800MB under valgrind)."));
-+                      " Check disabled by default."));
- 
- static cl::opt<bool>
- UseValgrind("enable-valgrind",