At boot time, we preallocate 32MB of RAM to reuse for all malloc()
requests by stbtt_RenderText(), which should be more than enough for the
primary use case (browsing web pages).
Give LibC malloc() and calloc() an array of 16 mem_tasks each, for now.
We will probably be removing this, in favor of giving each non-HolyC
library its own static memory pool, as we will do with stb_truetype.h in
a forthcoming commit.
