Fix gcc compilation of dsound_new

Add CMakeLists.txt and mostly fix gcc compilation of dsound_new. Although it is still not compilable, my PR fixes at least part of compilation issues.

It still fails for me with a lot of errors "undefined reference to FuncName@X" (see dsound_new_output.txt for details). I wonder: it's due to errors directly in the C code, what is possible too, or most likely, due to incorrect libraries linking?... I suspect I didn't add some library in my CMakeLists.txt at target_link_libraries line.

Also I didn't include dsound_convert.c in my CMakeLists.txt since it's taken as-is from Wine's dsound unlike other source files and has many conflicts with them. I doubt need I include it...

I just hope that it may work better than current (Wine's) dsound.

If you want to test it, you need to comment out `add_subdirectory(dsound)` in dll/directx/wine/CMakeLists.txt and uncomment `#add_subdirectory(dsound_new) # disabled in trunk` in dll/directx/CMakeLists.txt.