anchor.diff:      license = "GPLv2+";
   
       maintainers = [ stdenv.lib.maintainers.eelco ];
  -    
  +
       platforms = stdenv.lib.platforms.linux ++ stdenv.lib.platforms.darwin;
     };
   }
  +
  +//
  +
  +(if stdenv.isDarwin
  + then {
  +   patchPhase =
  +     # Apple's GCC doesn't recognize `-arch' (as of version 4.2.1, build 5666).
  +     '' echo "getting rid of the \`-arch' GCC option..."
  +        find -name Makefile\* -exec \
  +          sed -i {} -e's/DARWIN\(.*\)-arch [^ ]\+/DARWIN\1/g' \;
  +
  +        sed -i coregrind/link_tool_exe_darwin.in \
  +            -e 's/^my \$archstr = .*/my $archstr = "x86_64";/g'
  +     '';
  +
  +   preConfigure =
  +     # Shamelessly drag in MIG.
  +     '' mkdir -p "$TMPDIR/impure-deps/bin"
  +
  +        # MIG assumes the standard Darwin core utilities (e.g., `rm -d'), so
  +        # let it see the impure directories.
  +        cat > "$TMPDIR/impure-deps/bin/mig" <<EOF
  +#!/bin/sh
  +export PATH="/usr/bin:/bin:\$PATH"
  +exec /usr/bin/mig "\$@"
  +EOF
  +        chmod +x "$TMPDIR/impure-deps/bin/mig"
  +
  +        export PATH="$TMPDIR/impure-deps/bin:$PATH"
  +     '';
  + }
  + else {}))
  
positive.code:   buildInputs = stdenv.lib.optional (!stdenv.isDarwin) gdb;
  
    configureFlags =
      if stdenv.system == "x86_64-linux" then ["--enable-only64bit"] else [];
  
    postInstall = ''
      for i in $out/lib/valgrind/*.supp; do
  
negative.code: { stdenv, fetchurl, perl, gdb, autoconf, automake }:
  
  stdenv.mkDerivation (rec {
    name = "valgrind-3.6.1";
  
    src = fetchurl {
  