Bugs to fix:
-  Left-vram overflow when rendering text
-  A few key hits ignored after leaving the application (could not reproduce)
-  Lost keyboard control at startup (could not reproduce)
-  Back-light issues (0xa400012c on SH3, 0xa4050138 on SH4)

Simple improvements:
-  bopti:	Monochrome bitmaps blending modes
-  bopti:	Partial transparency
-  demo:	Try 284x124 at (-60, -28) (all disadvantages)
-  display:	Rectangle-based drawing functions
-  tales:	Test all font encodings
-  time:	Compute CLOCKS_PER_SEC
-  timer:	Add duration and frequency settings
-  core:	Add VBR handlers debugging information (if possible)
-  core:	Implement all callbacks and a complete user API

Modules to implement:
-  Serial communication
-  Sound playback and synthesizing
-  Handle errors within errno

Things to investigate:
-  Packed bit fields alignment
-  Registers that may need to be saved within setjmp()
-  Registers that may need to be saved and restored by gint
-  Possible bug when optimizing __attribute__((interrupt_handler))

Configuration:
-  ATEXIT_MAX (16)
-  RTC_CB_ARRAY_SIZE (5)
-  EVENTS_QUEUE_SIZE (64)
-  GINT_NO_SYSCALLS (undefined)