fix LLVM packages to work in darwin stdenv

pkgs/development/compilers/llvm/3.7/libc++/default.nix

@@ -12,15 +12,6 @@ stdenv.mkDerivation rec {
   preConfigure = ''
     # Get headers from the cxxabi source so we can see private headers not installed by the cxxabi package
     cmakeFlagsArray=($cmakeFlagsArray -DLIBCXX_CXX_ABI_INCLUDE_PATHS="$NIX_BUILD_TOP/libcxxabi-${version}.src/include")
-  '' +
-  stdenv.lib.optionalString stdenv.isDarwin ''
-    # instead of allowing libc++ to link with /usr/lib/libc++abi.dylib,
-    # force it to link with our copy
-    substituteInPlace lib/CMakeLists.txt \
-      --replace 'OSX_RE_EXPORT_LINE "/usr/lib/libc++abi.dylib' \
-                'OSX_RE_EXPORT_LINE "${libcxxabi}/lib/libc++abi.dylib' \
-      --replace '"''${CMAKE_OSX_SYSROOT}/usr/lib/libc++abi.dylib"' \
-                '"${libcxxabi}/lib/libc++abi.dylib"'
   '';
 
   patches = [ ./darwin.patch ];

pkgs/development/compilers/llvm/3.7/libc++abi.nix

@@ -27,7 +27,7 @@ stdenv.mkDerivation {
       done
       make install
       install -d 755 $out/include
-      install -m 644 ../include/cxxabi.h $out/include
+      install -m 644 ../include/*.h $out/include
     ''
     else ''
       install -d -m 755 $out/include $out/lib

pkgs/development/compilers/llvm/3.7/llvm.nix

@@ -11,6 +11,7 @@
 , ncurses
 , version
 , zlib
+, libcxxabi
 , compiler-rt_src
 }:
 
@@ -27,7 +28,8 @@ in stdenv.mkDerivation rec {
     mv compiler-rt-* $sourceRoot/projects/compiler-rt
   '';
 
-  buildInputs = [ perl groff cmake libxml2 python libffi ] /* ++ stdenv.lib.optional stdenv.isLinux valgrind */;
+  buildInputs = [ perl groff cmake libxml2 python libffi ]
+    ++ stdenv.lib.optional stdenv.isDarwin libcxxabi;
 
   propagatedBuildInputs = [ ncurses zlib ];
 
@@ -47,7 +49,7 @@ in stdenv.mkDerivation rec {
     "-DBUILD_SHARED_LIBS=ON"
     "-DLLVM_BINUTILS_INCDIR=${binutils}/include"
   ] ++ stdenv.lib.optionals ( isDarwin) [
-    "-DCMAKE_CXX_FLAGS=-stdlib=libc++"
+    "-DLLVM_ENABLE_LIBCXX=ON"
     "-DCAN_TARGET_i386=false"
   ];