Everywhere: Give stbtt its own 32MB static memory pool

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).

src/libtemple/libtemple.cpp

@@ -74,4 +74,8 @@ long time_jiffies() { return 0; }
 
 long time_now() { return 0; }
 
-void time_sleep(long duration) { }
+void time_sleep(long duration) { }
+
+void* truetype_malloc(int size) { return 0; }
+
+void truetype_free(void* ptr) { }