ctl: fix build with gcc47

pkgs/development/libraries/ctl/default.nix

@@ -8,7 +8,7 @@ stdenv.mkDerivation {
     sha256 = "16lzgbpxdyhykdwndj1i9vx3h4bfkxqqcrvasvgg70gb5raxj0mj";
   };
 
-  patches = [ ./patch.patch ];
+  patches = [ ./patch.patch ./gcc47.patch ];
 
   propagatedBuildInputs = [ ilmbase ];
 

pkgs/development/libraries/ctl/gcc47.patch

@@ -0,0 +1,15 @@
+ https://bugs.gentoo.org/426368
+ 
+ IlmCtl/CtlInterpreter.cpp | 1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/IlmCtl/CtlInterpreter.cpp
++++ b/IlmCtl/CtlInterpreter.cpp
+@@ -64,6 +64,7 @@
+ #include <fstream>
+ #include <algorithm>
+ #include <cassert>
++#include <unistd.h>
+ 
+ #ifdef WIN32
+     #include <io.h>