Fix warnings.

src/conio/ansi_cio.c

@@ -916,12 +916,12 @@ int ansi_readbyte_cb(void)
 
 int ansi_writebyte_cb(unsigned char ch)
 {
-	fwrite(&ch,1,1,stdout);
+	return(fwrite(&ch,1,1,stdout));
 }
 
 int ansi_writestr_cb(unsigned char *str, size_t len)
 {
-	fwrite(str,len,1,stdout);
+	return(fwrite(str,len,1,stdout));
 }
 
 int ansi_initio_cb(void)
@@ -954,6 +954,7 @@ int ansi_initio_cb(void)
 		atexit(ansi_fixterm);
 	}
 #endif
+	return(0);
 }
 
 #if defined(__BORLANDC__)

src/conio/bitmap_con.c

@@ -703,7 +703,7 @@ error_return:
 }
 
 /* vstatlock is held */
-static void bitmap_draw_cursor()
+static void bitmap_draw_cursor(void)
 {
 	int x;
 	int y;

src/conio/win32cio.c

@@ -833,7 +833,7 @@ void win32_getcustomcursor(int *s, int *e, int *r, int *b, int *v)
 	HANDLE				h;
 
 	if((h=GetStdHandle(STD_INPUT_HANDLE)) == INVALID_HANDLE_VALUE)
-		return(0);
+		return;
 
 	GetConsoleCursorInfo(h, &ci);
 	if(s)
@@ -854,7 +854,7 @@ void win32_setcustomcursor(int s, int e, int r, int b, int v)
 	HANDLE				h;
 
 	if((h=GetStdHandle(STD_INPUT_HANDLE)) == INVALID_HANDLE_VALUE)
-		return(0);
+		return;
 
 	ci.bVisible=v;
 	if(e>s)