diff --git a/pkgs/development/interpreters/octave/default.nix b/pkgs/development/interpreters/octave/default.nix
index b2e858a8d310..4763ddb445d4 100644
--- a/pkgs/development/interpreters/octave/default.nix
+++ b/pkgs/development/interpreters/octave/default.nix
@@ -1,6 +1,6 @@
-{stdenv, fetchurl, g77, readline, ncurses, perl}:
+{stdenv, fetchurl, g77, readline, ncurses, perl, flex}:
 
-assert readline != null && ncurses != null;
+assert readline != null && ncurses != null && flex != null;
 assert g77.langF77;
 
 stdenv.mkDerivation {
@@ -9,6 +9,6 @@ stdenv.mkDerivation {
     url = ftp://ftp.octave.org/pub/octave/bleeding-edge/octave-2.9.0.tar.bz2;
     md5 = "687a09033bc68f09810e947010bc8f29";
   };
-  buildInputs = [g77 readline ncurses perl];
+  buildInputs = [g77 readline ncurses perl flex];
   configureFlags = "--enable-readline --enable-dl --disable-static --enable-shared";
 }
diff --git a/pkgs/system/all-packages-generic.nix b/pkgs/system/all-packages-generic.nix
index 0f072f7145a0..e3dd452d8cf0 100644
--- a/pkgs/system/all-packages-generic.nix
+++ b/pkgs/system/all-packages-generic.nix
@@ -182,7 +182,10 @@ rec {
     inherit fetchurl stdenv;
   };
 
-  
+  mjpegtools = (import ../tools/video/mjpegtools) {
+    inherit fetchurl stdenv;
+  };
+ 
   ### SHELLS
 
   bash = (import ../shells/bash) {
@@ -262,7 +265,7 @@ rec {
   };
 
   octave = (import ../development/interpreters/octave) {
-    inherit fetchurl stdenv readline ncurses g77 perl;
+    inherit fetchurl stdenv readline ncurses g77 perl flex;
   };
 
   gnumake = (import ../development/tools/build-managers/gnumake) {