[base] Don't allocate `library->raster_pool' anymore.

It's unused after the following commits:

  [raster] Allocate render pool for mono rasterizer on the stack.
  [raster] Remove 5-level gray AA mode from monochrome rasterizer.

The value of FT_RENDER_POOL_SIZE still serves the purpose it used to
serve, which is, to adjust the pool size.  But the pool is now
allocated on the stack on demand.

* src/base/ftobjs.c (FT_New_Library, FT_Done_Library): Implement.
5 files changed