Amiga: header hygiene and palette-size constants

Add AMII_PALETTE_SIZE / AMIV_PALETTE_SIZE in amiconf.h to make the
actual populated portion of the init-map arrays explicit.  Drop the
redundant extern void exit() declaration.  Annotate Abort with
NORETURN in both amiconf.h and winproto.h; drop the duplicate Abort
declaration further down winproto.h.

Convert the bare-token "CLIPPING must be defined" assertion in
windefs.h into a real #error directive.

Comment in winext.h to disambiguate the three similarly named
amii*_init*map palette arrays.

include/amiconf.h

@@ -48,9 +48,8 @@ extern void nethack_exit(int);
 extern void amii_setpens(int);
 
 extern void getlind(const char *, char *, const char *);
-extern void exit(int);
 extern void CleanUp(void);
-extern void Abort(long);
+extern void Abort(long) NORETURN;
 extern int getpid(void);
 extern int kbhit(void);
 extern int WindowGetchar(void);
@@ -84,6 +83,10 @@ extern void ami_wininit_data(int);
 #define CHANGE_COLOR 1
 #define DEPTH 6 /* Maximum depth of the screen allowed */
 #define AMII_MAXCOLORS (1L << DEPTH)
+/* Number of palette entries actually populated in amii_init_map[] (AMII text
+ * mode) and amiv_init_map[] (AMIV tile mode).  Indices beyond these read 0. */
+#define AMII_PALETTE_SIZE 8
+#define AMIV_PALETTE_SIZE 32
 typedef unsigned short AMII_COLOR_TYPE;
 
 #define PORT_HELP "amii.hlp"

sys/amiga/windefs.h

@@ -29,7 +29,7 @@
 #include "func_tab.h"
 
 #ifndef CLIPPING
-CLIPPING must be defined for the AMIGA version
+#error "CLIPPING must be defined for the AMIGA version"
 #endif
 
 #undef LI

sys/amiga/winext.h

@@ -23,6 +23,17 @@ extern struct amii_DisplayDesc
     *amiIDisplay; /* the Amiga Intuition descriptor */
 extern struct window_procs amii_procs;
 extern struct window_procs amiv_procs;
+/* Three similarly-named palette arrays.  Note the position of the
+ * second underscore distinguishes them:
+ *   amii_initmap  = working/runtime palette (mutated by tile/tomb load
+ *                   and the in-game color editor).
+ *   amii_init_map = AMII (text-mode) compile-time defaults, 8 entries.
+ *   amiv_init_map = AMIV (tile-mode) compile-time defaults, 32 entries
+ *                   (mutated by ReadImageFile when a tile/tomb IFF
+ *                   carries its own CMAP).
+ * The naming is historical; sysflags.amii_curmap is yet another related
+ * array holding the user's saved color choices.
+ */
 extern unsigned short amii_initmap[AMII_MAXCOLORS];
 extern unsigned short amiv_init_map[AMII_MAXCOLORS];
 extern unsigned short amii_init_map[AMII_MAXCOLORS];

sys/amiga/winproto.h

@@ -59,7 +59,7 @@ int amikbhit(void);
 int WindowGetchar(void);
 WETYPE WindowGetevent(void);
 void amii_cleanup(void);
-void Abort(long rc);
+void Abort(long rc) NORETURN;
 void CleanUp(void);
 void flush_glyph_buffer(struct Window *w);
 void amiga_print_glyph(winid window, int color_index, int glyph);
@@ -120,8 +120,6 @@ void amii_display_file(const char *fn, boolean complain);
 void SetBorder(struct Gadget *gd);
 /* malloc/free provided by stdlib.h */
 
-void Abort(long rc);
-
 win_request_info *amii_ctrl_nhwindow(winid, int, win_request_info *);
 
 /* amirip.c */