diff --git a/Source/d_deh.c b/Source/d_deh.c
index 5e35f0dc..8f77da9a 100644
--- a/Source/d_deh.c
+++ b/Source/d_deh.c
@@ -1894,7 +1894,7 @@ void deh_procSounds(DEHFILE *fpin, FILE* fpout, char *line)
             S_sfx[indexnum].priority = value;
           else
             if (!strcasecmp(key,deh_sfxinfo[3]))  // Zero 1
-              S_sfx[indexnum].link = (sfxinfo_t *)value;
+              S_sfx[indexnum].link = (sfxinfo_t *)(intptr_t)value;
             else
               if (!strcasecmp(key,deh_sfxinfo[4]))  // Zero 2
                 S_sfx[indexnum].pitch = value;
@@ -1903,7 +1903,7 @@ void deh_procSounds(DEHFILE *fpin, FILE* fpout, char *line)
                   S_sfx[indexnum].volume = value;
                 else
                   if (!strcasecmp(key,deh_sfxinfo[6]))  // Zero 4
-                    S_sfx[indexnum].data = (void *) value; // killough 5/3/98: changed cast
+                    S_sfx[indexnum].data = (void *)(intptr_t) value; // killough 5/3/98: changed cast
                   else
                     if (!strcasecmp(key,deh_sfxinfo[7]))  // Neg. One 1
                       S_sfx[indexnum].usefulness = value;
diff --git a/Source/d_main.c b/Source/d_main.c
index 68b80d6e..672540b0 100644
--- a/Source/d_main.c
+++ b/Source/d_main.c
@@ -1501,7 +1501,7 @@ void D_DoomMain(void)
       // killough 5/2/98: this takes a memory
       // address as an integer on the command line!
 
-      statcopy = (void*) atoi(myargv[p+1]);
+      statcopy = (void*)(intptr_t) atoi(myargv[p+1]);
       puts("External statistics registered.");
     }
 
diff --git a/Source/d_net.c b/Source/d_net.c
index 03100e1e..c9989998 100644
--- a/Source/d_net.c
+++ b/Source/d_net.c
@@ -91,7 +91,7 @@ extern int  key_escape;                // phares
 //
 int NetbufferSize (void)
 {
-  return (int)&(((doomdata_t *)0)->cmds[netbuffer->numtics]); 
+  return (intptr_t)&(((doomdata_t *)0)->cmds[netbuffer->numtics]);
 }
 
 //
@@ -109,7 +109,7 @@ unsigned NetbufferChecksum (void)
 //    return 0;                 // byte order problems
 //#endif
 
-  l = (NetbufferSize () - (int)&(((doomdata_t *)0)->retransmitfrom))/4;
+  l = (NetbufferSize () - (intptr_t)&(((doomdata_t *)0)->retransmitfrom))/4;
   for (i=0 ; i<l ; i++)
     c += ((unsigned *)&netbuffer->retransmitfrom)[i] * (i+1);
 
diff --git a/Source/doomtype.h b/Source/doomtype.h
index 56843c3e..fa9e8575 100644
--- a/Source/doomtype.h
+++ b/Source/doomtype.h
@@ -34,6 +34,8 @@
 #include "config.h"
 #endif
 
+#include <stdint.h> // [FG] include for intptr_t types
+
 #ifndef __BYTEBOOL__
 #define __BYTEBOOL__
 // Fixed to use builtin bool type with C++.
diff --git a/Source/g_game.c b/Source/g_game.c
index e465cb0b..0b92b6e8 100644
--- a/Source/g_game.c
+++ b/Source/g_game.c
@@ -1252,8 +1252,8 @@ static void G_DoSaveGame(void)
 
   save_p = G_WriteOptions(save_p);    // killough 3/1/98: save game options
 
-  memcpy(save_p, &leveltime, sizeof save_p); //killough 11/98: save entire word
-  save_p += sizeof save_p;
+  memcpy(save_p, &leveltime, sizeof leveltime); //killough 11/98: save entire word
+  save_p += sizeof leveltime; // [FG] fix copy size and pointer progression
 
   // killough 11/98: save revenant tracer state
   *save_p++ = (gametic-basetic) & 255;
@@ -1359,8 +1359,8 @@ static void G_DoLoadGame(void)
 
   // get the times
   // killough 11/98: save entire word
-  memcpy(&leveltime, save_p, sizeof save_p);
-  save_p += sizeof save_p;
+  memcpy(&leveltime, save_p, sizeof leveltime);
+  save_p += sizeof leveltime; // [FG] fix copy size and pointer progression
 
   // killough 11/98: load revenant tracer state
   basetic = gametic - (int) *save_p++;
diff --git a/Source/m_menu.c b/Source/m_menu.c
index 287d2357..8b84477e 100644
--- a/Source/m_menu.c
+++ b/Source/m_menu.c
@@ -1949,7 +1949,7 @@ void M_DrawSetting(setup_menu_t* s)
 
   if (flags & S_YESNO)
     {
-      strcpy(menu_buffer,*s->var.def->location ? "YES" : "NO");
+      strcpy(menu_buffer,s->var.def->location->i ? "YES" : "NO");
       M_DrawMenuString(x,y,color);
       return;
     }
@@ -2020,7 +2020,7 @@ void M_DrawSetting(setup_menu_t* s)
   if (flags & (S_WEAP|S_CRITEM)) // weapon number or color range
     {
       sprintf(menu_buffer,"%d", *s->var.def->location);
-      M_DrawMenuString(x,y, flags & S_CRITEM ? *s->var.def->location : color);
+      M_DrawMenuString(x,y, flags & S_CRITEM ? s->var.def->location->i : color);
       return;
     }
 
@@ -2039,7 +2039,7 @@ void M_DrawSetting(setup_menu_t* s)
       
       // draw the paint chip
        
-      ch = *s->var.def->location;
+      ch = s->var.def->location->i;
       if (!ch) // don't show this item in automap mode
 	V_DrawPatchDirect (x+1,y,0,W_CacheLumpName("M_PALNO",PU_CACHE));
       else
@@ -2057,7 +2057,7 @@ void M_DrawSetting(setup_menu_t* s)
 
   if (flags & S_STRING)
     {
-      char *text = *(char **) s->var.def->location;
+      char *text = s->var.def->location->s;
 
       // Are we editing this string? If so, display a cursor under
       // the correct character.
@@ -2220,7 +2220,7 @@ void M_DrawInstructions()
   int flags = current_setup_menu[set_menu_itemon].m_flags;
 
   // killough 8/15/98: warn when values are different
-  if (flags & (S_NUM|S_YESNO) && def->current && *def->current!=*def->location)
+  if (flags & (S_NUM|S_YESNO) && def->current && def->current->i!=def->location->i)
     {
       int allow = allow_changes() ? 8 : 0;
       if (!(setup_gather | print_warning_about_changes | demoplayback))
@@ -3612,13 +3612,13 @@ void M_ResetDefaults()
 	for (l = setup_screens[setup_screen-1]; *l; l++)
 	  for (p = *l; !(p->m_flags & S_END); p++)
 	    if (p->m_flags & S_HASDEFPTR ? p->var.def == dp :
-		p->var.m_key == dp->location || 
-		p->m_mouse == dp->location ||
-		p->m_joy == dp->location)
+		p->var.m_key == &dp->location->i ||
+		p->m_mouse == &dp->location->i ||
+		p->m_joy == &dp->location->i)
 	      {
 		if (dp->isstr)
-		  free(*(char **) dp->location),
-		    *(char **) dp->location = strdup((char *)dp->defaultvalue);
+		  free(dp->location->s),
+		    dp->location->s = strdup(dp->defaultvalue.s);
 		else
 		  *dp->location = dp->defaultvalue;
 	
@@ -4581,7 +4581,7 @@ boolean M_Responder (event_t* ev)
 	    {
 	      if (ch == key_menu_enter)
 		{
-		  *ptr1->var.def->location = !*ptr1->var.def->location; // killough 8/15/98
+		  ptr1->var.def->location->i = !ptr1->var.def->location->i; // killough 8/15/98
 
 		  // phares 4/14/98:
 		  // If not in demoplayback, demorecording, or netgame,
@@ -4598,7 +4598,7 @@ boolean M_Responder (event_t* ev)
 		      if (allow_changes())  // killough 8/15/98
 			*ptr1->var.def->current = *ptr1->var.def->location;
 		      else
-			if (*ptr1->var.def->current != *ptr1->var.def->location)
+			if (ptr1->var.def->current->i != ptr1->var.def->location->i)
 			  warn_about_changes(S_LEVWARN); // killough 8/15/98
 
 		  if (ptr1->action)      // killough 10/98
@@ -4615,7 +4615,7 @@ boolean M_Responder (event_t* ev)
 		  ch -= 0x30; // out of ascii
 		  if (ch < 0 || ch > 9)
 		    return true; // ignore
-		  *ptr1->var.def->location = ch;
+		  ptr1->var.def->location->i = ch;
 		}
 	      if (ptr1->action)      // killough 10/98
 		ptr1->action();
@@ -4648,7 +4648,7 @@ boolean M_Responder (event_t* ev)
 			    warn_about_changes(S_BADVAL);
 			  else
 			    {
-			      *ptr1->var.def->location = value;
+			      ptr1->var.def->location->i = value;
 
 			      // killough 8/9/98: fix numeric vars
 			      // killough 8/15/98: add warning message
@@ -4659,9 +4659,9 @@ boolean M_Responder (event_t* ev)
 			      else
 				if (ptr1->var.def->current)
 				  if (allow_changes())  // killough 8/15/98
-				    *ptr1->var.def->current = value;
+				    ptr1->var.def->current->i = value;
 				  else
-				    if (*ptr1->var.def->current != value)
+				    if (ptr1->var.def->current->i != value)
 				      warn_about_changes(S_LEVWARN);
 
 			      if (ptr1->action)      // killough 10/98
@@ -4835,13 +4835,13 @@ boolean M_Responder (event_t* ev)
 		for (i = 0; (ptr2 = weap_settings[i]); i++)
 		  for (; !(ptr2->m_flags & S_END); ptr2++)
 		    if (ptr2->m_flags & S_WEAP && 
-			*ptr2->var.def->location == ch && ptr1 != ptr2)
+			ptr2->var.def->location->i == ch && ptr1 != ptr2)
 		      {
 			*ptr2->var.def->location = *ptr1->var.def->location;
 			goto end;
 		      }
 	      end:
-		*ptr1->var.def->location = ch;
+		ptr1->var.def->location->i = ch;
 	      }
 
 	    M_SelectDone(ptr1);       // phares 4/17/98
@@ -4887,7 +4887,7 @@ boolean M_Responder (event_t* ev)
 
 	    if (ch == key_menu_enter)               
 	      {
-		*ptr1->var.def->location = color_palette_x + 16*color_palette_y;
+		ptr1->var.def->location->i = color_palette_x + 16*color_palette_y;
 		M_SelectDone(ptr1);                         // phares 4/17/98
 		colorbox_active = false;
 		return true;
@@ -4926,7 +4926,7 @@ boolean M_Responder (event_t* ev)
 	      else if ((ch == key_menu_enter) ||
 		       (ch == key_menu_escape))
 		{
-		  *(char **) ptr1->var.def->location = chat_string_buffer;
+		  ptr1->var.def->location->s = chat_string_buffer;
 		  M_SelectDone(ptr1);   // phares 4/17/98
 		}
 	      
@@ -5011,13 +5011,13 @@ boolean M_Responder (event_t* ev)
 	    }
 	  else if (flags & S_COLOR)
 	    {
-	      int color = *ptr1->var.def->location;
+	      int color = ptr1->var.def->location->i;
         
 	      if (color < 0 || color > 255) // range check the value
 		color = 0;        // 'no show' if invalid
 
-	      color_palette_x = *ptr1->var.def->location & 15;
-	      color_palette_y = *ptr1->var.def->location >> 4;
+	      color_palette_x = ptr1->var.def->location->i & 15;
+	      color_palette_y = ptr1->var.def->location->i >> 4;
 	      colorbox_active = true;
 	    }
 	  else if (flags & S_STRING)
@@ -5030,7 +5030,7 @@ boolean M_Responder (event_t* ev)
 
 	      chat_string_buffer = malloc(CHAT_STRING_BFR_SIZE);
 	      strncpy(chat_string_buffer,
-		      *(char **) ptr1->var.def->location, CHAT_STRING_BFR_SIZE);
+		      ptr1->var.def->location->s, CHAT_STRING_BFR_SIZE);
 
 	      // guarantee null delimiter
 	      chat_string_buffer[CHAT_STRING_BFR_SIZE-1] = 0;
@@ -5038,8 +5038,8 @@ boolean M_Responder (event_t* ev)
 	      // set chat table pointer to working buffer
 	      // and free old string's memory.
 
-	      free(*(char **) ptr1->var.def->location);
-	      *(char **) ptr1->var.def->location = chat_string_buffer;
+	      free(ptr1->var.def->location->s);
+	      ptr1->var.def->location->s = chat_string_buffer;
 	      chat_index = 0; // current cursor position in chat_string_buffer
 	    }
 	  else if (flags & S_RESET)
diff --git a/Source/m_misc.c b/Source/m_misc.c
index bd43e906..b8afe962 100644
--- a/Source/m_misc.c
+++ b/Source/m_misc.c
@@ -96,6 +96,13 @@ extern char *chat_macros[], *wad_files[], *deh_files[];  // killough 10/98
 // killough 11/98: entirely restructured to allow options to be modified
 // from wads, and to consolidate with menu code
 
+// [FG] silence some "incompatible pointer types" GCC warnings here, as
+// pointers to integer and to union config_u are in fact interchangeable
+
+#ifdef __GNUC__
+#pragma GCC diagnostic ignored "-Wincompatible-pointer-types"
+#endif
+
 default_t defaults[] = {
   { //jff 3/3/98
     "config_help",
@@ -404,29 +411,29 @@ default_t defaults[] = {
 
   { // killough 10/98: preloaded files
     "wadfile_1",
-    (int *) &wad_files[0], NULL,
-    (int) "", {0}, string, ss_none, wad_no,
+    &wad_files[0], NULL,
+    {.s = ""}, {0}, string, ss_none, wad_no,
     "WAD file preloaded at program startup"
   },
 
   {
     "wadfile_2",
-    (int *) &wad_files[1], NULL,
-    (int) "", {0}, string, ss_none, wad_no,
+    &wad_files[1], NULL,
+    {.s = ""}, {0}, string, ss_none, wad_no,
     "WAD file preloaded at program startup"
   },
 
   {
     "dehfile_1",
-    (int *) &deh_files[0], NULL,
-    (int) "", {0}, string, ss_none, wad_no,
+    &deh_files[0], NULL,
+    {.s = ""}, {0}, string, ss_none, wad_no,
     "DEH/BEX file preloaded at program startup"
   },
 
   {
     "dehfile_2",
-    (int *) &deh_files[1], NULL,
-    (int) "", {0}, string, ss_none, wad_no,
+    &deh_files[1], NULL,
+    {.s = ""}, {0}, string, ss_none, wad_no,
     "DEH/BEX file preloaded at program startup"
   },
 
@@ -1099,71 +1106,71 @@ default_t defaults[] = {
 
   {
     "chatmacro0",
-    (int *) &chat_macros[0], NULL,
-    (int) HUSTR_CHATMACRO0, {0}, string, ss_chat, wad_yes,
+    &chat_macros[0], NULL,
+    {.s = HUSTR_CHATMACRO0}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 0 key"
   },
 
   {
     "chatmacro1",
-    (int *) &chat_macros[1], NULL,
-    (int) HUSTR_CHATMACRO1, {0}, string, ss_chat, wad_yes,
+    &chat_macros[1], NULL,
+    {.s = HUSTR_CHATMACRO1}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 1 key"
   },
 
   {
     "chatmacro2",
-    (int *) &chat_macros[2], NULL,
-    (int) HUSTR_CHATMACRO2, {0}, string, ss_chat, wad_yes,
+    &chat_macros[2], NULL,
+    {.s = HUSTR_CHATMACRO2}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 2 key"
   },
 
   {
     "chatmacro3",
-    (int *) &chat_macros[3], NULL,
-    (int) HUSTR_CHATMACRO3, {0}, string, ss_chat, wad_yes,
+    &chat_macros[3], NULL,
+    {.s = HUSTR_CHATMACRO3}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 3 key"
   },
 
   {
     "chatmacro4",
-    (int *) &chat_macros[4], NULL,
-    (int) HUSTR_CHATMACRO4, {0}, string, ss_chat, wad_yes,
+    &chat_macros[4], NULL,
+    {.s = HUSTR_CHATMACRO4}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 4 key"
   },
 
   {
     "chatmacro5",
-    (int *) &chat_macros[5], NULL,
-    (int) HUSTR_CHATMACRO5, {0}, string, ss_chat, wad_yes,
+    &chat_macros[5], NULL,
+    {.s = HUSTR_CHATMACRO5}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 5 key"
   },
 
   {
     "chatmacro6",
-    (int *) &chat_macros[6], NULL,
-    (int) HUSTR_CHATMACRO6, {0}, string, ss_chat, wad_yes,
+    &chat_macros[6], NULL,
+    {.s = HUSTR_CHATMACRO6}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 6 key"
   },
 
   {
     "chatmacro7",
-    (int *) &chat_macros[7], NULL,
-    (int) HUSTR_CHATMACRO7, {0}, string, ss_chat, wad_yes,
+    &chat_macros[7], NULL,
+    {.s = HUSTR_CHATMACRO7}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 7 key"
   },
 
   {
     "chatmacro8",
-    (int *) &chat_macros[8], NULL,
-    (int) HUSTR_CHATMACRO8, {0}, string, ss_chat, wad_yes,
+    &chat_macros[8], NULL,
+    {.s = HUSTR_CHATMACRO8}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 8 key"
   },
 
   {
     "chatmacro9",
-    (int *) &chat_macros[9], NULL,
-    (int) HUSTR_CHATMACRO9, {0}, string, ss_chat, wad_yes,
+    &chat_macros[9], NULL,
+    {.s = HUSTR_CHATMACRO9}, {0}, string, ss_chat, wad_yes,
     "chat string associated with 9 key"
   },
 
@@ -1665,6 +1672,10 @@ default_t defaults[] = {
   {NULL}         // last entry
 };
 
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
 static char *defaultfile;
 static boolean defaults_loaded = false;      // killough 10/98
 
@@ -1741,7 +1752,8 @@ void M_SaveDefaults (void)
 
   for (blanks = 1, line = 0, dp = defaults; ; dp++, blanks = 0)
     {
-      int brackets = 0, value;
+      int brackets = 0;
+      config_t value;
 
       for (;line < comment && comments[line].line <= dp-defaults; line++)
         if (*comments[line].text != '[' || (brackets = 1, config_help))
@@ -1773,7 +1785,7 @@ void M_SaveDefaults (void)
 
       if (config_help && !brackets)
 	if ((dp->isstr ? 
-	     fprintf(f,"[(\"%s\")]", (char *) dp->defaultvalue) :
+	     fprintf(f,"[(\"%s\")]", (char *) dp->defaultvalue.s) :
 	     dp->limit.min == UL ?
 	     dp->limit.max == UL ?
 	     fprintf(f, "[?-?(%d)]", dp->defaultvalue) :
@@ -1788,16 +1800,19 @@ void M_SaveDefaults (void)
       // killough 11/98:
       // Write out original default if .wad file has modified the default
       
-      value = dp->modified ? dp->orig_default : (int) *dp->location;
+      if (dp->isstr)
+        value.s = dp->modified ? dp->orig_default.s : dp->location->s;
+      else
+        value.i = dp->modified ? dp->orig_default.i : dp->location->i;
 
       //jff 4/10/98 kill super-hack on pointer value
       // killough 3/6/98:
       // use spaces instead of tabs for uniform justification
 
       if (!dp->isstr ? fprintf(f, "%-25s %5i\n", dp->name, 
-			       strncmp(dp->name, "key_", 4) ? value :
-			       I_DoomCode2ScanCode(value)) == EOF :
-	  fprintf(f,"%-25s \"%s\"\n", dp->name, (char *) value) == EOF)
+			       strncmp(dp->name, "key_", 4) ? value.i :
+			       I_DoomCode2ScanCode(value.i)) == EOF :
+	  fprintf(f,"%-25s \"%s\"\n", dp->name, (char *) value.s) == EOF)
 	goto error;
     }
 
@@ -1856,17 +1871,17 @@ boolean M_ParseOption(const char *p, boolean wad)
       if (wad && !dp->modified)                       // Modified by wad
 	{                                             // First time modified
 	  dp->modified = 1;                           // Mark it as modified
-	  dp->orig_default = *dp->location;           // Save original default
+	  dp->orig_default.s = dp->location->s;         // Save original default
 	}
       else
-	free(*(char **) dp->location);                // Free old value
+	free(dp->location->s);                // Free old value
 
-      *(char **) dp->location = strdup(strparm+1);    // Change default value
+      dp->location->s = strdup(strparm+1);    // Change default value
 
       if (dp->current)                                // Current value
 	{
-	  free(*(char **) dp->current);               // Free old value
-	  *(char **) dp->current = strdup(strparm+1); // Change current value
+	  free(dp->current->s);               // Free old value
+	  dp->current->s = strdup(strparm+1); // Change current value
 	}
     }
   else
@@ -1886,12 +1901,12 @@ boolean M_ParseOption(const char *p, boolean wad)
 	      if (!dp->modified)         // First time it's modified by wad
 		{
 		  dp->modified = 1;      // Mark it as modified
-		  dp->orig_default = *dp->location;  // Save original default
+		  dp->orig_default.i = dp->location->i;  // Save original default
 		}
 	      if (dp->current)           // Change current value
-		*dp->current = parm;
+		dp->current->i = parm;
 	    }
-	  *dp->location = parm;          // Change default
+	  dp->location->i = parm;          // Change default
 	}
     }
 
@@ -1956,8 +1971,10 @@ void M_LoadDefaults (void)
   // edit these strings (i.e. chat macros in the Chat Strings Setup screen).
 
   for (dp = defaults; dp->name; dp++)
-    *dp->location =
-      dp->isstr ? (int) strdup((char *) dp->defaultvalue) : dp->defaultvalue;
+    if (dp->isstr)
+      dp->location->s = strdup(dp->defaultvalue.s);
+    else
+      dp->location->i = dp->defaultvalue.i;
 
   // check for a custom default file
 
@@ -2217,8 +2234,8 @@ boolean WritePCXfile(char *filename, byte *data, int width,
 #define BI_RGB 0L
 
 typedef unsigned short uint_t;
-typedef unsigned long dword_t;
-typedef long     long_t;
+typedef uint32_t dword_t; // [FG] unsigned long
+typedef int32_t long_t; // [FG] long
 typedef unsigned char ubyte_t;
 
 #ifdef _WIN32
diff --git a/Source/m_misc.h b/Source/m_misc.h
index 3192a685..4e305bca 100644
--- a/Source/m_misc.h
+++ b/Source/m_misc.h
@@ -52,12 +52,21 @@ extern int screenshot_pcx;                               // killough 10/98
 //
 // killough 11/98: totally restructured
 
+// [FG] use a union of integer and string pointer to store config values, instead
+// of type-punning string pointers to integers which won't work on 64-bit systems anyway
+
+typedef union config_u
+{
+  int i;
+  char *s;
+} config_t;
+
 typedef struct default_s
 {
   const char *const name;                   // name
-  int  *const location;                     // default variable
-  int  *const current;                      // possible nondefault variable
-  int   const defaultvalue;                 // built-in default value
+  config_t *const location;                 // default variable
+  config_t *const current;                  // possible nondefault variable
+  config_t  const defaultvalue;             // built-in default value
   struct {int min, max;} const limit;       // numerical limits
   enum {number, string} const isstr;        // number or string
   ss_types const setupscreen;               // setup screen this appears on
@@ -68,7 +77,7 @@ typedef struct default_s
 
   struct default_s *first, *next;           // hash table pointers
   int modified;                             // Whether it's been modified
-  int orig_default;                         // Original default, if modified
+  config_t orig_default;                    // Original default, if modified
   struct setup_menu_s *setup_menu;          // Xref to setup menu item, if any
 } default_t;
 
diff --git a/Source/p_saveg.c b/Source/p_saveg.c
index c8726828..017bb453 100644
--- a/Source/p_saveg.c
+++ b/Source/p_saveg.c
@@ -43,7 +43,7 @@ byte *save_p;
 
 // Pads save_p to a 4-byte boundary
 //  so that the load/save works on SGI&Gecko.
-#define PADSAVEP()    do { save_p += (4 - ((int) save_p & 3)) & 3; } while (0)
+#define PADSAVEP()    do { save_p += (4 - ((intptr_t) save_p & 3)) & 3; } while (0)
 //
 // P_ArchivePlayers
 //
@@ -94,7 +94,7 @@ void P_UnArchivePlayers (void)
         for (j=0 ; j<NUMPSPRITES ; j++)
           if (players[i]. psprites[j].state)
             players[i]. psprites[j].state =
-              &states[ (int)players[i].psprites[j].state ];
+              &states[ (size_t)players[i].psprites[j].state ];
       }
 }
 
@@ -438,10 +438,10 @@ void P_UnArchiveThinkers (void)
       PADSAVEP();
       memcpy (mobj, save_p, sizeof(mobj_t));
       save_p += sizeof(mobj_t);
-      mobj->state = states + (int) mobj->state;
+      mobj->state = states + (size_t) mobj->state;
 
       if (mobj->player)
-        (mobj->player = &players[(int) mobj->player - 1]) -> mo = mobj;
+        (mobj->player = &players[(size_t) mobj->player - 1]) -> mo = mobj;
 
       P_SetThingPosition (mobj);
       mobj->info = &mobjinfo[mobj->type];
@@ -761,7 +761,7 @@ void P_UnArchiveSpecials (void)
           ceiling_t *ceiling = Z_Malloc (sizeof(*ceiling), PU_LEVEL, NULL);
           memcpy (ceiling, save_p, sizeof(*ceiling));
           save_p += sizeof(*ceiling);
-          ceiling->sector = &sectors[(int)ceiling->sector];
+          ceiling->sector = &sectors[(size_t)ceiling->sector];
           ceiling->sector->ceilingdata = ceiling; //jff 2/22/98
 
           if (ceiling->thinker.function)
@@ -778,10 +778,10 @@ void P_UnArchiveSpecials (void)
           vldoor_t *door = Z_Malloc (sizeof(*door), PU_LEVEL, NULL);
           memcpy (door, save_p, sizeof(*door));
           save_p += sizeof(*door);
-          door->sector = &sectors[(int)door->sector];
+          door->sector = &sectors[(size_t)door->sector];
 
           //jff 1/31/98 unarchive line remembered by door as well
-          door->line = (int)door->line!=-1? &lines[(int)door->line] : NULL;
+          door->line = (size_t)door->line!=-1? &lines[(size_t)door->line] : NULL;
 
           door->sector->ceilingdata = door;       //jff 2/22/98
           door->thinker.function = T_VerticalDoor;
@@ -795,7 +795,7 @@ void P_UnArchiveSpecials (void)
           floormove_t *floor = Z_Malloc (sizeof(*floor), PU_LEVEL, NULL);
           memcpy (floor, save_p, sizeof(*floor));
           save_p += sizeof(*floor);
-          floor->sector = &sectors[(int)floor->sector];
+          floor->sector = &sectors[(size_t)floor->sector];
           floor->sector->floordata = floor; //jff 2/22/98
           floor->thinker.function = T_MoveFloor;
           P_AddThinker (&floor->thinker);
@@ -808,7 +808,7 @@ void P_UnArchiveSpecials (void)
           plat_t *plat = Z_Malloc (sizeof(*plat), PU_LEVEL, NULL);
           memcpy (plat, save_p, sizeof(*plat));
           save_p += sizeof(*plat);
-          plat->sector = &sectors[(int)plat->sector];
+          plat->sector = &sectors[(size_t)plat->sector];
           plat->sector->floordata = plat; //jff 2/22/98
 
           if (plat->thinker.function)
@@ -825,7 +825,7 @@ void P_UnArchiveSpecials (void)
           lightflash_t *flash = Z_Malloc (sizeof(*flash), PU_LEVEL, NULL);
           memcpy (flash, save_p, sizeof(*flash));
           save_p += sizeof(*flash);
-          flash->sector = &sectors[(int)flash->sector];
+          flash->sector = &sectors[(size_t)flash->sector];
           flash->thinker.function = T_LightFlash;
           P_AddThinker (&flash->thinker);
           break;
@@ -837,7 +837,7 @@ void P_UnArchiveSpecials (void)
           strobe_t *strobe = Z_Malloc (sizeof(*strobe), PU_LEVEL, NULL);
           memcpy (strobe, save_p, sizeof(*strobe));
           save_p += sizeof(*strobe);
-          strobe->sector = &sectors[(int)strobe->sector];
+          strobe->sector = &sectors[(size_t)strobe->sector];
           strobe->thinker.function = T_StrobeFlash;
           P_AddThinker (&strobe->thinker);
           break;
@@ -849,7 +849,7 @@ void P_UnArchiveSpecials (void)
           glow_t *glow = Z_Malloc (sizeof(*glow), PU_LEVEL, NULL);
           memcpy (glow, save_p, sizeof(*glow));
           save_p += sizeof(*glow);
-          glow->sector = &sectors[(int)glow->sector];
+          glow->sector = &sectors[(size_t)glow->sector];
           glow->thinker.function = T_Glow;
           P_AddThinker (&glow->thinker);
           break;
@@ -861,7 +861,7 @@ void P_UnArchiveSpecials (void)
           fireflicker_t *flicker = Z_Malloc (sizeof(*flicker), PU_LEVEL, NULL);
           memcpy (flicker, save_p, sizeof(*flicker));
           save_p += sizeof(*flicker);
-          flicker->sector = &sectors[(int)flicker->sector];
+          flicker->sector = &sectors[(size_t)flicker->sector];
           flicker->thinker.function = T_FireFlicker;
           P_AddThinker (&flicker->thinker);
           break;
@@ -874,7 +874,7 @@ void P_UnArchiveSpecials (void)
           elevator_t *elevator = Z_Malloc (sizeof(*elevator), PU_LEVEL, NULL);
           memcpy (elevator, save_p, sizeof(*elevator));
           save_p += sizeof(*elevator);
-          elevator->sector = &sectors[(int)elevator->sector];
+          elevator->sector = &sectors[(size_t)elevator->sector];
           elevator->sector->floordata = elevator; //jff 2/22/98
           elevator->sector->ceilingdata = elevator; //jff 2/22/98
           elevator->thinker.function = T_MoveElevator;
diff --git a/Source/z_zone.c b/Source/z_zone.c
index d52df9a3..d4f23981 100644
--- a/Source/z_zone.c
+++ b/Source/z_zone.c
@@ -63,7 +63,7 @@ static const char rcsid[] = "$Id: z_zone.c,v 1.13 1998/05/12 06:11:55 killough E
 #define CACHE_ALIGN 32
 
 // size of block header
-#define HEADER_SIZE 32
+//#define HEADER_SIZE 32
 
 // Minimum chunk size at which blocks are allocated
 #define CHUNK_SIZE 32
@@ -107,6 +107,11 @@ typedef struct memblock {
 
 } memblock_t;
 
+/* size of block header
+ * cph - base on sizeof(memblock_t), which can be larger than CHUNK_SIZE on
+ * 64bit architectures */
+static const size_t HEADER_SIZE = (sizeof(memblock_t)+CHUNK_SIZE-1) & ~(CHUNK_SIZE-1);
+
 static memblock_t *rover;                // roving pointer to memory blocks
 static memblock_t *zone;                 // pointer to first block
 static memblock_t *zonebase;             // pointer to entire zone memory
@@ -244,7 +249,7 @@ void Z_Init(void)
   // Align on cache boundary
 
   zone = (memblock_t *) ((char *) zonebase + CACHE_ALIGN -
-                         ((unsigned) zonebase & (CACHE_ALIGN-1)));
+                         ((uintptr_t) zonebase & (CACHE_ALIGN-1)));
 
   rover = zone;                            // Rover points to base of zone mem
   zone->next = zone->prev = zone;          // Single node
diff --git a/configure.ac b/configure.ac
index f9bd1313..feb93f3b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,12 +18,14 @@ PKG_CHECK_MODULES([SDL_net],   [SDL_net])
 AC_DEFINE([MY_SDL_VER], [1], [This is WinMBF])
 
 # Checks for header files.
-AC_CHECK_HEADERS([fcntl.h limits.h malloc.h stddef.h stdlib.h string.h unistd.h])
+AC_CHECK_HEADERS([fcntl.h limits.h malloc.h stddef.h stdint.h stdlib.h string.h unistd.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_CHECK_HEADER_STDBOOL
 AC_C_INLINE
 AC_C_RESTRICT
+AC_TYPE_INTPTR_T
+AC_TYPE_UINTPTR_T
 AC_TYPE_SIZE_T
 AC_CHECK_TYPES([ptrdiff_t])