Rather than trying to force things in via library constructors
and weak symbols and --whole-archive and pkg-config tricks, just
add new functions ncdirect_core_init() and notcurses_core_init().
libnotcurses has ncdirect_init() and notcurses_init(), which pass
through to these. apps linking against notcurses-core ought use
the _core_ variants directly. This gets exactly the linkage we
want, everywhere. Convert many PoCs to _core_ variants. #1301
Signed-off-by: nick black <dankamongmen@gmail.com>
Extract `libnotcurses-core` from `libnotcurses`. The former contains everything except multimedia code. The latter contains multimedia stuff (a wrapper around FFmpeg or OIIO). If built with `-DUSE_MULTIMEDIA=none`, there will not be any `libnotcurses.so` generated. `libnotcurses.so` uses library constructors/destructors to insert its implementation into the `ncvisual` stack at runtime. Users linking `-lnotcurses` will get the full implementation; users linking `-lnotcurses-core` only will get the stack less multimedia code.
The upshot of this is that someone can compile/install only `libnotcurses-core`, and a program linked against it will work just fine. This eliminates the need to install the full (large) dependency stack of the multimedia code unless necessary. This will hopefully be useful for e.g. installers etc. Closes#339.
ncplane_destroy() needs to call ncplane_reparent_family(), not
ncplane_reparent() as it was doing (closes#1291). ->absy and
->absx actually are absolute; return them directly for an O(1)
ncplane_abs_yx() (down from O(N), huzzah). Add some unit tests
related to destroying and reparenting (#1286). Add ncplane_abs_y()
and ncplane_abs_x(), document them, etc.
