diff --git a/pkgs/development/compilers/gcc/6/darwin-const-correct.patch b/pkgs/development/compilers/gcc/6/darwin-const-correct.patch
new file mode 100644
index 000000000000..a9b9b85acab2
--- /dev/null
+++ b/pkgs/development/compilers/gcc/6/darwin-const-correct.patch
@@ -0,0 +1,25 @@
+From 5972cd58bde3bc8bacfe994e5b127c411241f255 Mon Sep 17 00:00:00 2001
+From: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>
+Date: Tue, 3 Jan 2017 05:36:40 +0000
+Subject: [PATCH] 	* config/darwin-driver.c (darwin_driver_init):
+ Const-correctness 	fixes for first_period and second_period variables.
+
+git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@244010 138bc75d-0d04-0410-961f-82ee72b054a4
+---
+diff --git a/gcc/config/darwin-driver.c b/gcc/config/darwin-driver.c
+index 0c4f0cd..e3ed79d 100644
+--- a/gcc/config/darwin-driver.c
++++ b/gcc/config/darwin-driver.c
+@@ -299,10 +299,10 @@ darwin_driver_init (unsigned int *decoded_options_count,
+   if (vers_string != NULL)
+     {
+       char *asm_major = NULL;
+-      char *first_period = strchr(vers_string, '.');
++      const char *first_period = strchr(vers_string, '.');
+       if (first_period != NULL)
+ 	{
+-	  char *second_period = strchr(first_period+1, '.');
++	  const char *second_period = strchr(first_period+1, '.');
+ 	  if (second_period  != NULL)
+ 	    asm_major = xstrndup (vers_string, second_period-vers_string);
+ 	  else
diff --git a/pkgs/development/compilers/gcc/6/default.nix b/pkgs/development/compilers/gcc/6/default.nix
index c6fac16a76ca..b4e588f6b143 100644
--- a/pkgs/development/compilers/gcc/6/default.nix
+++ b/pkgs/development/compilers/gcc/6/default.nix
@@ -73,7 +73,8 @@ let version = "6.3.0";
       # The GNAT Makefiles did not pay attention to CFLAGS_FOR_TARGET for its
       # target libraries and tools.
       ++ optional langAda ../gnat-cflags.patch
-      ++ optional langFortran ../gfortran-driving.patch;
+      ++ optional langFortran ../gfortran-driving.patch
+      ++ optional stdenv.isDarwin ./darwin-const-correct.patch; # Kill this after 6.3.0
 
     javaEcj = fetchurl {
       # The `$(top_srcdir)/ecj.jar' file is automatically picked up at