* move win32/config0.h -> config/config_windows0.h
* move win32/stdint.h -> msvc/stdint.h
* move posix/defines.h -> config/config_unix.h
* add config.h - brings in config_(windows|unix).h as required
* add config.h to *.cpp
* Self-contain FFmpegSource2 with required function defines wrapped with
__UNIX__ instead of the now removed defines.h.
* Edit aegisub_vs2008.vcproj to remove explicit inclusion of config.h, also
change VCPreBuildEventTool to create windows_config.h from
windows_config0.h. Add msvc to include path.
* Change configure to create ./acconf.h instead of posix/acconf.h
This will allow us to create a more standard and platform agnostic way of
configuration aegsisub during build time.
Originally committed to SVN as r2621.
