Use main(void) when not taking arguments

scrsize.c

@@ -37,7 +37,7 @@
 #include <stdio.h>
 
 int
-main()
+main(void)
 {
     char *cp;
     Display *dpy;

w3mbookmark.c

@@ -181,7 +181,7 @@ insert_bookmark(char *bmark, struct parsed_tagarg *data)
 }
 
 int
-main(int argc, char *argv[])
+main(void)
 {
     extern char *getenv();
     char *p;

w3mhelperpanel.c

@@ -164,7 +164,7 @@ editMailcap(char *mailcap, struct parsed_tagarg *args)
 }
 
 int
-main(int argc, char *argv[])
+main(void)
 {
     Str mailcapfile;
     extern char *getenv();