If std::common_type<range::index_type>... finds a common index_type
among all the zipped ranges, pass that common type through as
zip<...>::index_type. Otherwise, set zip<...>::index_type to void.
This allows enumerate(zip(...))) to report a better index_type.
This eliminates the only place that zip<>'s template parameter list is
written out in the source, which will allow later commits to change the
template parameter list.
Trim the bitmap's current width and height to be not more than its
parent. Otherwise, an automatic screen resize, such as triggered when
playing the robot briefings in Descent 2, will give the window a new
smaller bm_data, but continue to use the old dimensions. This then
causes load_briefing_screen -> gr_bitmap_scale_to -> scale_line to write
off the end of the smaller bm_data, causing memory corruption and
eventually a crash.
enum game_mode_flags must be visible in common code, which does not
define DXX_BUILD_DESCENT_II. To avoid One Definition Rule errors,
game_mode_flags must have the same definition in all files.
Fortunately, the DXX_BUILD_DESCENT_II definition is a superset of the
common definition, so the preprocessor guards can be replaced with
advisory comments.
Fixes: 2b718da343 ("Use enum class for Game_mode, Newdemo_game_mode")
Remove the workaround added for issue #289 [1]. That issue covered a
miscompilation by early versions of gcc-4.9. gcc-4.9.x is no longer
supported, so the workaround is no longer needed.
[1]: https://github.com/dxx-rebirth/dxx-rebirth/issues/289
Change it from the level number on which the path was created to a
true/false flag. The previous logic only tested whether the number was
equal to the current level number.
This also fixes a bug where the action was not available on the first
secret level, since that level is `-1`, and the value was set to `-1` to
indicate that it should be enabled.
