Add a cross-platform port of cctools.

This basically is binutils for Mac OS X, but ported to work on
(GNU/)Linux and FreeBSD.

And it's up-to-date as well! I'm mentioning this, because it was quite
hard to find a recent port of it and I just accidentally stumbled on it
while trying to do the port by myself.

So thanks to @tpoechtrager for doing this.

Also, I've added two more patches, which essentially are:

 * ld-rpath-nonfinal:
     This allows -rpath to be used for linking non-final builds, which
     was allowed for earlier versions of cctools and got a check for
     that in more recent versions.

 * ld-ignore-rpath-link:
     Ignores the -rpath-link option, because the cross-wrapper uses it
     in different places. Unfortunately, the cctools linker doesn't
     support it, so we might need to implement this later if it's
     possible (I'm not a Mach-O man^H^H^Hexpert).

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/os-specific/darwin/cctools-port/default.nix

@@ -0,0 +1,55 @@
+{ stdenv, cross, fetchurl, autoconf, automake, libtool
+, libcxx, llvm, clang, openssl, libuuid
+}:
+
+stdenv.mkDerivation rec {
+  name = "cctools-port-${version}";
+  version = "845";
+
+  src = fetchurl {
+    url = "https://github.com/tpoechtrager/cctools-port/archive/"
+        + "cctools-${version}-ld64-136-1.tar.gz";
+    sha256 = "06pg6h1g8avgx4j6cfykdpggf490li796gzhhyqn27jsagli307i";
+  };
+
+  buildInputs = [
+    autoconf automake libtool libcxx llvm clang openssl libuuid
+  ];
+
+  patches = [ ./ld-rpath-nonfinal.patch ./ld-ignore-rpath-link.patch ];
+
+  enableParallelBuilding = true;
+
+  postPatch = ''
+    patchShebangs tools
+    sed -i -e 's/which/type -P/' tools/*.sh
+    sed -i -e 's|clang++|& -I${libcxx}/include/c++/v1|' cctools/autogen.sh
+
+    # Workaround for https://www.sourceware.org/bugzilla/show_bug.cgi?id=11157
+    cat > cctools/include/unistd.h <<EOF
+    #ifdef __block
+    #  undef __block
+    #  include_next "unistd.h"
+    #  define __block __attribute__((__blocks__(byref)))
+    #else
+    #  include_next "unistd.h"
+    #endif
+    EOF
+  '';
+
+  preConfigure = ''
+    cd cctools
+    sh autogen.sh
+  '';
+
+  configureFlags = [
+    "CXXFLAGS=-I${libcxx}/include/c++/v1"
+    "--target=${cross.config}"
+  ];
+
+  meta = {
+    homepage = "http://www.opensource.apple.com/source/cctools/";
+    description = "Mac OS X Compiler Tools (cross-platform port)";
+    license = stdenv.lib.licenses.apsl20;
+  };
+}

pkgs/os-specific/darwin/cctools-port/ld-ignore-rpath-link.patch

@@ -0,0 +1,16 @@
+diff --git a/cctools/ld64/src/ld/Options.cpp b/cctools/ld64/src/ld/Options.cpp
+index 2565518..9250016 100644
+--- a/cctools/ld64/src/ld/Options.cpp
++++ b/cctools/ld64/src/ld/Options.cpp
+@@ -2522,6 +2522,11 @@ void Options::parse(int argc, const char* argv[])
+ 					throw "missing argument to -rpath";
+ 				fRPaths.push_back(path);
+ 			}
++			else if ( strcmp(arg, "-rpath-link") == 0 ) {
++				const char* path = argv[++i];
++				if ( path == NULL )
++					throw "missing argument to -rpath-link";
++			}
+ 			else if ( strcmp(arg, "-read_only_stubs") == 0 ) {
+ 				fReadOnlyx86Stubs = true;
+ 			}

pkgs/os-specific/darwin/cctools-port/ld-rpath-nonfinal.patch

@@ -0,0 +1,31 @@
+diff --git a/cctools/ld64/src/ld/Options.cpp b/cctools/ld64/src/ld/Options.cpp
+index 9250016..91d54ec 100644
+--- a/cctools/ld64/src/ld/Options.cpp
++++ b/cctools/ld64/src/ld/Options.cpp
+@@ -4175,23 +4175,9 @@ void Options::checkIllegalOptionCombinations()
+ 		throw "-r and -dead_strip cannot be used together";
+ 
+ 	// can't use -rpath unless targeting 10.5 or later
+-	if ( fRPaths.size() > 0 ) {
+-		if ( !minOS(ld::mac10_5, ld::iOS_2_0) )
+-			throw "-rpath can only be used when targeting Mac OS X 10.5 or later";
+-		switch ( fOutputKind ) {
+-			case Options::kDynamicExecutable:
+-			case Options::kDynamicLibrary:
+-			case Options::kDynamicBundle:
+-				break;
+-			case Options::kStaticExecutable:
+-			case Options::kObjectFile:
+-			case Options::kDyld:
+-			case Options::kPreload:
+-			case Options::kKextBundle:
+-				throw "-rpath can only be used when creating a dynamic final linked image";
+-		}
+-	}
+-	
++	if ( fRPaths.size() > 0 && !minOS(ld::mac10_5, ld::iOS_2_0) )
++		throw "-rpath can only be used when targeting Mac OS X 10.5 or later";
++
+ 	if ( fPositionIndependentExecutable ) {
+ 		switch ( fOutputKind ) {
+ 			case Options::kDynamicExecutable:

pkgs/top-level/all-packages.nix

@@ -6546,7 +6546,13 @@ let
 
   cramfsswap = callPackage ../os-specific/linux/cramfsswap { };
 
-  darwin.xcode = callPackage ../os-specific/darwin/xcode { };
+  darwin = {
+    cctools = forceNativeDrv (callPackage ../os-specific/darwin/cctools-port {
+      cross = assert crossSystem != null; crossSystem;
+    });
+
+    xcode = callPackage ../os-specific/darwin/xcode {};
+  };
 
   devicemapper = lvm2;