del warn(NULL)

The message displayed by `warn(NULL)` makes no one happy.

configure.ac

@@ -2,7 +2,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.69])
-AC_INIT([sendwol], [0.10], [https://github.com/KusaReMKN/sendwol/issue])
+AC_INIT([sendwol], [0.11], [https://github.com/KusaReMKN/sendwol/issue])
 AM_INIT_AUTOMAKE([foreign])
 AC_CONFIG_SRCDIR([sendwol.c])
 AC_CONFIG_HEADERS([config.h])

sendwol.1

@@ -53,7 +53,7 @@ By default,
 .Pa $HOME/.sendwol
 and
 .Pa /etc/ethers
-are looked up in this order.
+are looked up in this order if they exist.
 The specified file is looked up before them.
 If this option is specified more than once,
 those specified later will be looked up first.

sendwol.c

@@ -103,17 +103,12 @@ main(int argc, char *argv[])
 		goto dberror;
 
 	homesendwol = home_sendwol();
-	if (homesendwol != NULL) {
+	if (homesendwol != NULL)
 		if (push_dblist(&list, homesendwol) == -1) {
-dberror:		warn(NULL);
-			warnx("database files are not available");
+dberror:		warnx("database files are not available");
 			free_dblist(list);
 			list = NULL;
 		}
-	} else {
-		warn(NULL);
-		warnx("~/.sendwol is not available");
-	}
 
 	forcev4 = 0;
 	forcev6 = 0;
@@ -140,7 +135,6 @@ dberror:		warn(NULL);
 			if (list == NULL)
 				break;
 			if (push_dblist(&list, optarg) == -1) {
-				warn(NULL);
 				warnx("database files are not available");
 				free_dblist(list);
 				list = NULL;
@@ -308,8 +302,10 @@ home_sendwol(void)
 
 	length = snprintf(NULL, 0, HOME_SENDWOL, home) + 1;
 	buffer = (char *)malloc(length);
-	if (buffer == NULL)
+	if (buffer == NULL) {
+		warn("malloc");
 		return NULL;
+	}
 
 	snprintf(buffer, length, HOME_SENDWOL, home);
 
@@ -403,8 +399,10 @@ push_dblist(struct dblist **restrict headp, const char *restrict path)
 	struct dblist *temp;
 
 	temp = (struct dblist *)malloc(sizeof(*temp));
-	if (temp == NULL)
+	if (temp == NULL) {
+		warn("malloc");
 		return -1;
+	}
 
 	temp->dbl_next = *headp;
 	temp->dbl_path = path;