Reworked mapc+no SDL+no i18n and neverball/neverputt+SDL+i18n distinction.

Reworked mapc+no SDL+no i18n and neverball/neverputt+SDL+i18n distinction.

  * Removed unneeded headers from the "core" modules.

  Most importantly, moved lang.h  from base_config.h to config.h. Thus
  the core  modules (shared  across all apps)  and mapc  couldn't care
  less about whether they are built with  ENABLE_NLS set to 1 or 0. No
  hybrid builds should result.

  * Added back 'main' un-definition, this time in the Makefile.

  MinGW's 'sdl-config  --cflags' outputs  -Dmain=SDL_main in  order to
  allow  SDL  do  initialisation  and  other  Windows  magic  for  the
  so-called GUI apps, including  standard output redirection to files.
  We don't want  this for mapc, though. (And it  won't work anyway, if
  we do not link with 'sdl-config --libs'.)

git-svn-id: https://s.snth.net/svn/neverball/trunk@1285 78b8d119-cf0a-0410-b17c-f493084dd1d7