deskew: ensure libtiff can be found at runtime

pkgs/applications/graphics/deskew/default.nix

···
   buildPhase = ''
     runHook preBuild
     patchShebangs ./Scripts
+
+    # Deskew insists on using dlopen to load libtiff, we insist it links against it.
+    sed -i -e 's/{$DEFINE DYNAMIC_DLL_LOADING}//' Imaging/LibTiff/LibTiffDynLib.pas
+    sed -i -e 's/if LibTiffDynLib\.LoadTiffLibrary then//' Imaging/LibTiff/ImagingTiffLib.pas
+    # Make sure libtiff is in the RPATH, so that Nix can find and track the runtime dependency
+    export NIX_LDFLAGS="$NIX_LDFLAGS -rpath ${lib.getLib libtiff}/lib"
     pushd Scripts && ./compile.sh && popd
     runHook postBuild
   '';