diff --git a/pkgs/development/compilers/gcc-apple64/default.nix b/pkgs/development/compilers/gcc-apple64/default.nix
index ec16fae79774..ffb29da2f80c 100644
--- a/pkgs/development/compilers/gcc-apple64/default.nix
+++ b/pkgs/development/compilers/gcc-apple64/default.nix
@@ -8,23 +8,29 @@ assert langC;
 assert stdenv.isDarwin;
 assert langF77 -> gmp != null;
 
+let
+  version  = "4.2.1";   # Upstream GCC version, from `gcc/BASE-VER'.
+  revision = "5666.3";  # Apple's fork revision number.
+in
 stdenv.mkDerivation ({
-  name = "gcc-4.2.1-apple-5646";
+  name = "gcc-apple-${version}.${revision}";
+
   builder = ./builder.sh;
-  src = 
+
+  src =
     stdenv.lib.optional /*langC*/ true (fetchurl {
-      url = http://www.opensource.apple.com/tarballs/gcc/gcc-5646.tar.gz;
-      sha256 = "13jghyb098104kfym96iwwdvbj6snnws2c92h48lbd4fmyf1iv24";
+      url = "http://www.opensource.apple.com/tarballs/gcc/gcc-${revision}.tar.gz";
+      sha256 = "0nq1szgqx9ryh1qsn5n6yd55gpvf56wr8f7w1jzabb8idlvz8ikc";
     }) ++
     stdenv.lib.optional langCC (fetchurl {
       url = http://www.opensource.apple.com/tarballs/libstdcxx/libstdcxx-39.tar.gz ;
-      sha256 = "1fy6j41rhxdsm19sib9wygjl5l54g8pm13c6y5x13f40mavw1mma";
+      sha256 = "ccf4cf432c142778c766affbbf66b61001b6c4f1107bc2b2c77ce45598786b6d";
     }) ;
 
   enableParallelBuilding = true;
 
   libstdcxx = "libstdcxx-39";
-  sourceRoot = "gcc-5646/";
+  sourceRoot = "gcc-${revision}/";
   patches =
     [./pass-cxxcpp.patch ]
     ++ (if noSysDirs then [./no-sys-dirs.patch] else []);