octavePackages.ltfat: Set LD_LIBRARY_PATH for building packages

Some Octave packages ship C/C++/Fortran code that needs to be compiled
and linked against Octave's internal shared objects. Previously, ld
could not find these packages because $LD_LIBRARY_PATH was empty.

pkgs/development/interpreters/octave/build-octave-package.nix

@@ -123,6 +123,10 @@ stdenv.mkDerivation (
       else
         preBuild;
 
+    # Add Octave's shared objects to ld library path for some packages which
+    # need to link their C/C++/Fortran code against Octave's internals.
+    LD_LIBRARY_PATH = lib.makeLibraryPath nativeBuildInputs';
+
     buildPhase = ''
       runHook preBuild