[ntsc-1.2] Import libleo from Decompollaborate/n64dd (#2104)

* Create stack.h for STACK/STACK_TOP

* Import libleo from Decompollaborate/n64dd

Co-authored-by: Anghelo Carvajal <angheloalf95@gmail.com>
Co-authored-by: Elliptic Ellipsis <elliptic.ellipsis@gmail.com>

* Use (unsigned) int when in mdebug

* Apply suggestions from code review

Co-authored-by: Tharo <17233964+Thar0@users.noreply.github.com>

* Use && in leocmdex.c

* Use proper names for character tables, revert sNonKanjiIndices

* Fix incorrect OSMesg casts

* Use LEO_ERROR_GOOD even where docs say 0

Co-authored-by: Tharo <17233964+Thar0@users.noreply.github.com>

* Remove "Presumably" comment

* Whitespace

* Remove redundant (debug-only) returns

---------

Co-authored-by: Anghelo Carvajal <angheloalf95@gmail.com>
Co-authored-by: Elliptic Ellipsis <elliptic.ellipsis@gmail.com>
Co-authored-by: Tharo <17233964+Thar0@users.noreply.github.com>

src/boot/boot_main.c

@@ -1,5 +1,6 @@
 #include "global.h"
 #include "boot.h"
+#include "stack.h"
 #if PLATFORM_N64
 #include "cic6105.h"
 #endif

src/boot/idle.c

@@ -1,4 +1,5 @@
 #include "global.h"
+#include "stack.h"
 #include "terminal.h"
 
 #pragma increment_block_number "gc-eu:64 gc-eu-mq:64 gc-jp:64 gc-jp-ce:64 gc-jp-mq:64 gc-us:64 gc-us-mq:64"

src/boot/z_std_dma.c

@@ -20,6 +20,7 @@
  */
 #include "global.h"
 #include "fault.h"
+#include "stack.h"
 #include "terminal.h"
 #if PLATFORM_N64
 #include "n64dd.h"