Make empire, empsched and files catch extra operands

This also avoids a dead increment ap++ in src/client/main.c reported
by the Clang Static Analyzer.

src/client/main.c

@@ -138,6 +138,11 @@ main(int argc, char **argv)
 	}
 	uname = pwd->pw_name;
     }
+    if (*ap) {
+	fprintf(stderr, "%s: extra operand %s\n", argv[0], *ap);
+	fprintf(stderr, "Try -h for help.\n");
+	exit(1);
+    }
 
     getsose();
     if (auxfname && (auxfp = fopen(auxfname, "a")) == NULL) {

src/util/empsched.c

@@ -92,6 +92,12 @@ main(int argc, char *argv[])
 	}
     }
 
+    if (argc - optind > 1) {
+	fprintf(stderr, "%s: extra operand %s\n", argv[0], argv[optind+1]);
+	fprintf(stderr, "Try -h for help.\n");
+	exit(1);
+    }
+
     if (emp_config(config_file) < 0)
 	exit(1);
 

src/util/files.c

@@ -105,6 +105,12 @@ main(int argc, char *argv[])
 	}
     }
 
+    if (argv[optind]) {
+	fprintf(stderr, "%s: does not take operands\n", argv[0]);
+	fprintf(stderr, "Try -h for help.\n");
+	exit(1);
+    }
+
     empfile_init();
     if (emp_config(config_file) < 0)
 	exit(1);