#24 modplug-tools configury patch

[Ozkan Sezer]

The attached patch does the following:

• Removes AC_PROG_CXX from configure.ac: all the tools are C-only.
• Removes AC_PROG_LIBTOOL from configure.ac: I can't understand
  the reason for its existence. The only thing it does is doing rpath
  linkage when I use a custom installation directory for libmodplug..
  (which is annoying..)