trivial warn_unused_result squashing

Made the mistake of recompiling the F9 mdadm rpm which has a patch to
remove -Werror and add "-Wp,-D_FORTIFY_SOURCE -O2" which turns on lots
of errors:

config.c:568: warning: ignoring return value of asprintf
Assemble.c:411: warning: ignoring return value of asprintf
Assemble.c:413: warning: ignoring return value of asprintf
super0.c:549: warning: ignoring return value of posix_memalign
super0.c:742: warning: ignoring return value of posix_memalign
super0.c:812: warning: ignoring return value of posix_memalign
super1.c:692: warning: ignoring return value of posix_memalign
super1.c:1039: warning: ignoring return value of posix_memalign
super1.c:1155: warning: ignoring return value of posix_memalign
super-ddf.c:508: warning: ignoring return value of posix_memalign
super-ddf.c:645: warning: ignoring return value of posix_memalign
super-ddf.c:696: warning: ignoring return value of posix_memalign
super-ddf.c:715: warning: ignoring return value of posix_memalign
super-ddf.c:1476: warning: ignoring return value of posix_memalign
super-ddf.c:1603: warning: ignoring return value of posix_memalign
super-ddf.c:1614: warning: ignoring return value of posix_memalign
super-ddf.c:1842: warning: ignoring return value of posix_memalign
super-ddf.c:2013: warning: ignoring return value of posix_memalign
super-ddf.c:2140: warning: ignoring return value of write
super-ddf.c:2143: warning: ignoring return value of write
super-ddf.c:2147: warning: ignoring return value of write
super-ddf.c:2150: warning: ignoring return value of write
super-ddf.c:2162: warning: ignoring return value of write
super-ddf.c:2169: warning: ignoring return value of write
super-ddf.c:2172: warning: ignoring return value of write
super-ddf.c:2176: warning: ignoring return value of write
super-ddf.c:2181: warning: ignoring return value of write
super-ddf.c:2686: warning: ignoring return value of posix_memalign
super-ddf.c:2690: warning: ignoring return value of write
super-ddf.c:3070: warning: ignoring return value of posix_memalign
super-ddf.c:3254: warning: ignoring return value of posix_memalign
bitmap.c:128: warning: ignoring return value of posix_memalign
mdmon.c:94: warning: ignoring return value of write
mdmon.c:221: warning: ignoring return value of pipe
mdmon.c:327: warning: ignoring return value of write
mdmon.c:330: warning: ignoring return value of chdir
mdmon.c:335: warning: ignoring return value of dup
monitor.c:415: warning: rv may be used uninitialized in this function

...some of these like the write() ones are not so trivial so save those
fixes for the next patch.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/config.c b/config.c
index f471cf3..9aa8be4 100644
--- a/config.c
+++ b/config.c
@@ -564,10 +564,12 @@ void mailfromline(char *line)
 		if (alert_mail_from == NULL)
 			alert_mail_from = strdup(w);
 		else {
-			char *t= NULL;
-			asprintf(&t, "%s %s", alert_mail_from, w);
-			free(alert_mail_from);
-			alert_mail_from = t;
+			char *t = NULL;
+
+			if (asprintf(&t, "%s %s", alert_mail_from, w) > 0) {
+				free(alert_mail_from);
+				alert_mail_from = t;
+			}
 		}
 	}
 }