xap_helper.h: include signal.h for sig* functions

This is documented by all sig* manpages of FreeBSD and Linux,
but only OpenBSD fails to build without this header.

diff --git a/lib/PublicInbox/xap_helper.h b/lib/PublicInbox/xap_helper.h
index 493a24f46a2a596d8a8f773a86101207d829fb50..0f16d316fab0b09ff0e2dc5b0444448ed180dc9f 100644 (file)
--- a/lib/PublicInbox/xap_helper.h
+++ b/lib/PublicInbox/xap_helper.h
@@ -30,6 +30,7 @@
 #include <fcntl.h>
 #include <limits.h>
 #include <search.h>
+#include <signal.h>
 #include <stdio.h>
 #include <string.h>
 #include <sysexits.h>