Don't unnecessarily call alarm when duration is zero

.gitignore

@@ -1 +1,2 @@
 herbe
+.ccls-cache

TODO.md

@@ -0,0 +1,4 @@
+* Handle multiple notifications at the same time
+* Properly handle duration = 0
+* Keyboard shortcut to dismiss and accept notifications (also mouse)
+* Properly print new lines

herbe.c

@@ -67,7 +67,9 @@ int main(int argc, char *argv[])
 		die("Usage: %s body", argv[0]);
 
 	signal(SIGALRM, expire);
-	alarm(duration);
+
+	if (duration != 0)
+		alarm(duration);
 
 	display = XOpenDisplay(0);