Reduce overlay dependencies on global.h (8) (#2478)

* move variables into z64environment.h

* z_room.h

* z64sram.h, z64ss_sram.h, z64font.h, kanread.h

* z64lifemeter.h, z64debug.h, debug_arena.h

* buffers.h

* remove z_bgcheck global

* gamealloc.h

* suggestions

* .bdd

src/code/z_construct.c

@@ -1,7 +1,9 @@
-#include "global.h"
 #include "map.h"
 #include "regs.h"
+#include "segment_symbols.h"
 #include "versions.h"
+#include "z64lifemeter.h"
+#include "z64interface.h"
 #include "z64ocarina.h"
 #include "z64play.h"
 #include "z64save.h"