build: Don't use JAVA_CPPFLAGS, FT2_CPPFLAGS everywhere when making .df files. *.cc -> *.df rule now stops build when it fails (as it should have done before). * libinterp/Makefile.am: Remove FONTCONFIG_CPPFLAGS, FT2_CPPFLAGS, JAVA_CPPFLAGS from defaulte *.cc -> *.df rule. Abort make if rule errors out. * libinterp/corefcn/module.mk: Add overriding *.cc -> *.df rule for files which use (FONTCONFIG|FT2)_CPPFLAGS. * libinterp/octave-value/module.mk: Add overriding *.cc -> *.df rule for files which use JAVA_CPPFLAGS.

#include <octave/oct.h>

DEFUN_DLD (helloworld, args, nargout,
           "Hello World Help String")
{
  int nargin = args.length ();

  octave_stdout << "Hello World has "
                << nargin << " input arguments and "
                << nargout << " output arguments.\n";

  return octave_value_list ();
}