Fix prototypes for GCC 15.

--- fairymax-4.8/fmax4_8w.c	2025-07-03 16:55:20.256068541 +0100
+++ fairymax-4.8/fmax4_8w.c	2025-07-03 16:55:14.601630048 +0100
@@ -122,13 +122,13 @@
 centr[32],
 n[]=".*XKNBRQEWFMACHG?x+knbrqewfmachg";        /* piece symbols on printout*/
 
-pboard()
+void pboard()
 {int i;
  i=-1;W(++i<128)printf(" %c",(i&15)==BW&&(i+=15-BW)?10:n[b[i]&31]);
 }
          
 
-D(k,q,l,e,E,z,n)        /* recursive minimax search, k=moving side, n=depth*/
+int D(k,q,l,e,E,z,n)    /* recursive minimax search, k=moving side, n=depth*/
 int k,q,l,e,E,z,n;      /* (q,l)=window, e=current eval. score, E=e.p. sqr.*/
 {                       /* e=score, z=prev.dest; J,Z=hashkeys; return score*/
  int j,r,m,v,d,h,i,F,G,P,V,f=J,g=Z,C,s,flag,FF;
@@ -334,7 +334,7 @@
 }
 
 
-InitEngine()
+void InitEngine()
 {
  int i, j;
 
@@ -342,7 +342,7 @@
  srand(GetTickCount());
 }
 
-InitGame()
+void InitGame()
 {
  int i,j;
 
@@ -401,7 +401,7 @@
 	printf("feature done=1\n");
 }
                                          
-int LoadGame(char *name)
+void LoadGame(char *name)
 {
         int i, j, count=0; char c, buf[80];
         static int currentVariant;
@@ -535,7 +535,7 @@
                         continue;
 		}
 		if (!fgets(line, 256, stdin))
-			return;
+			return 0;
 		if (line[0] == '\n')
 			continue;
 		sscanf(line, "%s", command);
@@ -587,7 +587,7 @@
 		}
 		if (!strcmp(command, "quit"))
                         /* exit engine */
-			return;
+			return 0;
 		if (!strcmp(command, "force")) {
                         /* computer plays neither */
                         Computer = EMPTY;