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_room.c

@@ -1,5 +1,6 @@
 #include "libu64/debug.h"
 #include "ultra64/gs2dex.h"
+#include "buffers.h"
 #include "fault.h"
 #include "gfx.h"
 #include "gfx_setupdl.h"
@@ -18,11 +19,10 @@
 #include "z64audio.h"
 #include "z64play.h"
 #include "z64player.h"
+#include "z64room.h"
 #include "z64save.h"
 #include "z64skin_matrix.h"
 
-#include "global.h"
-
 Vec3f D_801270A0 = { 0.0f, 0.0f, 0.0f };
 
 // unused