Modern C compiler warn about the usage of declaring variables with out type
which then default to int.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
--- unclutter-1.09.orig/unclutter.c	2007-02-06 00:13:12.000000000 +0100
+++ unclutter-1.09/unclutter.c	2016-07-30 16:44:37.462489217 +0200
@@ -37,14 +37,15 @@
 #include <X11/Xutil.h>
 #include <X11/Xproto.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include "vroot.h"
 
 char *progname;
-pexit(str)char *str;{
+int pexit(str)char *str;{
     fprintf(stderr,"%s: %s\n",progname,str);
     exit(1);
 }
-usage(){
+void usage(void){
     pexit("usage:\n\
 	-display <display>\n\
 	-idle <seconds>		time between polls to detect idleness.\n\
@@ -87,7 +88,7 @@
  * return true if window has a wm_name and the start of it matches
  * one of the given names to avoid
  */
-nameinlist(display,window)
+int nameinlist(display,window)
 Display *display;
 Window window;
 {
@@ -109,7 +110,7 @@
  * return true if window has a wm_name and one of the given names to avoid
  * matches anywhere in that string
  */
-matchinlist(display,window)
+int matchinlist(display,window)
 Display *display;
 Window window;
 {
@@ -131,7 +132,7 @@
 /*
  * create a small 1x1 cursor with all pixels masked out on the given screen.
  */
-createnullcursor(display,root)
+Cursor createnullcursor(display,root)
 Display *display;
 Window root;
 {
@@ -155,7 +156,8 @@
     return cursor;
 }
 
-main(argc,argv)char **argv;{
+int main(argc,argv)
+int argc; char **argv;{
     Display *display;
     int screen,oldx = -99,oldy = -99,numscreens;
     int doroot = 0, jitter = 0, idletime = 5, usegrabmethod = 0, waitagain = 0,