Adding tesseract, an OCR engine I just found but never tried.

svn path=/nixpkgs/trunk/; revision=26952

pkgs/applications/graphics/tesseract/default.nix

@@ -0,0 +1,20 @@
+{ stdenv, fetchurl, libtiff }:
+
+stdenv.mkDerivation {
+  name = "tesseract-3.0.0";
+
+  src = fetchurl {
+    url = http://tesseract-ocr.googlecode.com/files/tesseract-3.00.tar.gz;
+    sha256 = "111r9hy1rcs2ch4kdi9dkzwch3xg38vv379sf3cjpkswkigx8clw";
+  };
+
+  buildInputs = [ libtiff ];
+
+  meta = {
+    description = "OCR engine";
+    homepage = http://code.google.com/p/tesseract-ocr/;
+    license = "Apache2.0";
+    maintainers = with stdenv.lib.maintainers; [viric];
+    platforms = with stdenv.lib.platforms; linux;
+  };
+}

pkgs/top-level/all-packages.nix

@@ -6862,6 +6862,8 @@ let
     withKde = getConfig [ "taskJuggler" "kde" ] false;
   };
 
+  tesseract = callPackage ../applications/graphics/tesseract { };
+
   thinkingRock = callPackage ../applications/misc/thinking-rock { };
 
   thunderbird = thunderbird3;