Revive Amiga port for NetHack 3.7

Update the Amiga Intuition window port (AMII/AMIV) for the 3.7
window_procs API. Key changes:

- Update all window function signatures for 3.7
- Add assembly trampolines for AmigaOS register-based callbacks
- Convert all K&R function definitions to C99
- Add cross-compilation build system (cross-pre1/pre2/post.370)
  using bebbo's m68k-amigaos-gcc with -noixemul -std=gnu17 -m68000
- Clipping fixes: viewport centering, simplified ScrollRaster,
  duplicate Ctrl-R suppression, glyph buffer invalidation
- Add menucolor support in menu rendering
- Move native txt2iff.c and xpm2iff.c to outdated/
- Add nethack.cnf and README.amiga

include/amiconf.h

@@ -48,13 +48,9 @@ typedef long off_t;
 #define PATHLEN 130
 
 /* data librarian defs */
-#ifndef NOCWD_ASSUMPTIONS
-#define DLBFILE "NetHack:nhdat"   /* main library */
-#define DLBFILE2 "NetHack:nhsdat" /* sound library */
-#else
 #define DLBFILE "nhdat"   /* main library */
-#define DLBFILE2 "nhsdat" /* sound library */
-#endif
+/* nhsdat sound library not used in 3.7 */
+#undef DLBFILE2
 
 #ifndef CROSS_TO_AMIGA
 #define FILENAME_CMP stricmp /* case insensitive */

include/winami.h

@@ -22,6 +22,7 @@ typedef struct amii_mi {
     char gselector;      /* Group selector */
     char canselect;      /* Can user select this entry. */
     char attr;           /* Attribute for the line. */
+    int color;           /* Color for the line (from menucolors). */
     char *str;           /* The text of the item. */
 } amii_menu_item;
 

include/winprocs.h

@@ -13,8 +13,11 @@
 enum wp_ids { wp_tty = 1, wp_X11, wp_Qt, wp_mswin, wp_curses,
               wp_chainin, wp_chainout, wp_safestartup, wp_shim,
               wp_hup, wp_guistubs, wp_ttystubs,
+#if defined(AMIGA)
+              wp_amii, wp_amiv,
+#endif
 #ifdef OUTDATED_STUFF
-              wp_mac, wp_Gem, wp_Gnome, wp_amii, wp_amiv,
+              wp_mac, wp_Gem, wp_Gnome,
 #endif
               wp_trace	// XXX do we need this?  should chainin/out get an id? TBD
 };