go1.5: Fix references to go1.4

pkgs/development/compilers/go/1.5.nix

@@ -11,6 +11,12 @@ let
     find $out -name "*.c" -delete
     cp -rf $out/bin/* $out/share/go/bin/
   '';
+
+  removeReferences = [ go_1_4 ];
+
+  removeExpr = refs: lib.flip lib.concatMapStrings refs (ref: ''
+    | sed "s,${ref},$(echo "${ref}" | sed "s,$NIX_STORE/[^-]*,$NIX_STORE/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee,"),g" \
+  '');
 in
 
 stdenv.mkDerivation rec {
@@ -105,8 +111,18 @@ stdenv.mkDerivation rec {
     ./all.bash
   '';
 
+  preFixup = ''
+    while read file; do
+      cat $file ${removeExpr removeReferences} > $file.tmp
+      mv $file.tmp $file
+      chmod +x $file
+    done < <(find $out/share/go/pkg/bootstrap/bin -type f 2>/dev/null)
+  '';
+
   setupHook = ./setup-hook.sh;
 
+  disallowedReferences = [ go_1_4 ];
+
   meta = with stdenv.lib; {
     branch = "1.5";
     homepage = http://golang.org/;