Patches for DOSBox to add mt32emu MIDI device

dosbox-0.74-3-mt32-patch.diff - diff file to be applied to official DOSBox release v.0.74-3 source distribution.

dosbox-SVN-r4319-mt32-patch.diff - diff file to be applied to official DOSBox sources SVN r4319 (and up, hopefully).
                                   It uses a bit different and clear approach introduced since SVN r3836.

How to build a patched version of DOSBox
========================================
This describes the steps necessary to produce a DOSBox binary with built-in MT-32 emulation using the GNU toolchain.
Note, builds with Microsoft Visual Studio or Xcode are not covered here. On Windows, MSYS can be used.

1. Ensure that the mt32emu library is built and installed in the system. Typically, the library headers should appear
   under the /usr/local/include directory and the library binary itself should be in /usr/local/lib. Usual steps

     cd <munt source directory>
     cmake .
     make
     [sudo] make install

   should do the job.

2. Apply the patch file that corresponds to the DOSBox version being compiled, like this:

     cd <DOSBox source directory>
     patch -p1 < <munt source directory>/DOSBox-mt32-patch/dosbox-0.74-3-mt32-patch.diff

3. Proceed with autogen and configure, as is normally done to build DOSBox from sources.
4. Adjust DOSBox configuration to pick up the ROM files, etc.
