Match stack_pointer with C code (#530)

* Remove useless comment

* Small amounts of documenting, official names, and use some new knowledge to match what was previously thought to be only possible with hasm.

* Define the proper type for the stack_pointer function, and come up with a solution for GCC builds that should hopefully work.

* Partial revert to support getting the actual stack pointer for GCC builds

* Come up with a better GCC build option for getting the stack pointer

* Update the score

src/camera.c

@@ -224,6 +224,7 @@ s32 get_viewport_count(void) {
 /**
  * Return the index of the active view.
  * 0-3 is players 1-4, and 4-7 is the same, but with 4 added on for cutscenes.
+ * Official Name: camGetMode
  */
 s32 get_current_viewport(void) {
     return gActiveCameraID;