Test at compile time whether siginfo_t is usable for --remote (#119).

src/main/help.c

@@ -399,11 +399,11 @@ void display_help(void)
 		{ "-U", "--store-and-forward", N_("FILE"),
 		 N_("write all input to FILE before writing to output"),
 		 { 0, 0, 0, 0} },
-#ifdef SA_SIGINFO
+#ifdef SIGINFO_PROVIDES_PID
 		{ "-R", "--remote", N_("PID"),
 		 N_("update settings of process PID"),
 		 { 0, 0, 0, 0} },
-#endif				/* SA_SIGINFO */
+#endif				/* SIGINFO_PROVIDES_PID */
 		{ "", NULL, NULL, NULL, { 0, 0, 0, 0} },
 		{ "-P", "--pidfile", N_("FILE"),
 		 N_("save process ID in FILE"),

src/main/remote.c

@@ -21,7 +21,7 @@
 #include <sys/time.h>
 #include <sys/stat.h>
 
-#ifdef SA_SIGINFO
+#ifdef SIGINFO_PROVIDES_PID
 void pv_error(pvstate_t, char *, ...);
 
 struct remote_msg {
@@ -405,10 +405,10 @@ void pv_remote_fini(void)
 {
 }
 
-#else				/* !SA_SIGINFO */
+#else				/* !SIGINFO_PROVIDES_PID */
 
 /*
- * Dummy stubs for remote control when we don't have SA_SIGINFO.
+ * Dummy stubs for remote control when we don't have SIGINFO_PROVIDES_PID.
  */
 void pv_remote_init(void)
 {