diff --git a/pkgs/development/compilers/gcc/5/default.nix b/pkgs/development/compilers/gcc/5/default.nix
index 6decc4c8cc3..fc007fe447b 100644
--- a/pkgs/development/compilers/gcc/5/default.nix
+++ b/pkgs/development/compilers/gcc/5/default.nix
@@ -32,8 +32,7 @@
 , gnat ? null
 , libpthread ? null, libpthreadCross ? null  # required for GNU/Hurd
 , stripped ? true
-, gnused ? null
-, binutils ? null
+, CF ? null
 }:
 
 assert langJava     -> zip != null && unzip != null
@@ -45,11 +44,8 @@ assert langVhdl     -> gnat != null;
 # LTO needs libelf and zlib.
 assert libelf != null -> zlib != null;
 
-# Make sure we get GNU sed.
-assert stdenv.isDarwin -> gnused != null;
-
-# Need c++filt on darwin
-assert stdenv.isDarwin -> binutils != null;
+# Make sure we get CoreFoundation.
+assert stdenv.isDarwin -> CF != null;
 
 # The go frontend is written in c++
 assert langGo -> langCC;
@@ -286,11 +282,6 @@ stdenv.mkDerivation ({
     ++ (optionals (cross != null) [binutilsCross])
     ++ (optionals langAda [gnatboot])
     ++ (optionals langVhdl [gnat])
-
-    # The builder relies on GNU sed (for instance, Darwin's `sed' fails with
-    # "-i may not be used with stdin"), and `stdenvNative' doesn't provide it.
-    ++ (optional stdenv.isDarwin gnused)
-    ++ (optional stdenv.isDarwin binutils)
     ;
 
   NIX_LDFLAGS = stdenv.lib.optionalString  stdenv.isSunOS "-lm -ldl";
@@ -301,14 +292,10 @@ stdenv.mkDerivation ({
     export CXXFLAGS_FOR_TARGET="-Wl,-rpath,$prefix/lib/amd64 $CXXFLAGS_FOR_TARGET"
     export CFLAGS_FOR_TARGET="-Wl,-rpath,$prefix/lib/amd64 $CFLAGS_FOR_TARGET"
   '' + stdenv.lib.optionalString stdenv.isDarwin ''
-    if SDKROOT=$(/usr/bin/xcrun --show-sdk-path); then
-      configureFlagsArray+=(--with-native-system-header-dir=$SDKROOT/usr/include)
-      makeFlagsArray+=( \
-       CFLAGS_FOR_BUILD=-F$SDKROOT/System/Library/Frameworks \
-       CFLAGS_FOR_TARGET=-F$SDKROOT/System/Library/Frameworks \
-       FLAGS_FOR_TARGET=-F$SDKROOT/System/Library/Frameworks \
-      )
-    fi
+    configureFlagsArray+=(
+      --with-sysroot="${stdenv.libc}"
+      --with-native-system-header-dir=/include
+    )
   '';
 
   dontDisableStatic = true;
@@ -475,10 +462,10 @@ stdenv.mkDerivation ({
                                           ++ optionals javaAwtGtk [ gmp mpfr ]
                                           ++ optional (libpthread != null) libpthread)));
 
-  EXTRA_TARGET_CFLAGS =
-    if cross != null && libcCross != null
+  extraFlags =
+    (if cross != null && libcCross != null
     then "-idirafter ${libcCross}/include"
-    else null;
+    else "") + optionalString stdenv.isDarwin " -F${CF}/Library/Frameworks";
 
   EXTRA_TARGET_LDFLAGS =
     if cross != null && libcCross != null
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index d0a088519b6..6150eb4f521 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -3868,6 +3868,8 @@ let
     libcCross = if crossSystem != null then libcCross else null;
 
     isl = isl_0_14;
+
+    inherit (darwin) CF;
   }));
 
   gfortran = if !stdenv.isDarwin then gfortran49