Minor update to defines and Makefile to avoid compile warnings

when building logsave.

src/logsave.c

@@ -13,6 +13,9 @@
 #ifndef _XOPEN_SOURCE
 #define _XOPEN_SOURCE 600 /* for inclusion of sa_handler in Solaris */
 #endif
+#ifndef HAVE_SIGNAL_H
+#define HAVE_SIGNAL_H
+#endif
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -23,7 +26,9 @@
 #include <fcntl.h>
 #include <time.h>
 #include <errno.h>
+#ifdef HAVE_SIGNAL_H
 #include <signal.h>
+#endif
 #ifdef HAVE_GETOPT_H
 #include <getopt.h>
 #else