getlimits: print SIGRTMIN and SIGRTMAX

* src/getlimits.c (SIGRTMIN): Define to zero if signal.h does not define
this constant.
(SIGRTMAX): Define to SIGRTMIN - 1 if signal.h does not define this
constant.
(main): Print SIGRTMIN and SIGRTMAX.

src/getlimits.c

@@ -17,6 +17,7 @@
 /* Written by Pádraig Brady  */
 
 #include <config.h>             /* sets _FILE_OFFSET_BITS=64 etc. */
+#include <signal.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <float.h>
@@ -54,6 +55,14 @@
 # define OFF64_T_MIN TYPE_MINIMUM (off64_t)
 #endif
 
+#ifndef SIGRTMIN
+# define SIGRTMIN 0
+# undef SIGRTMAX
+#endif
+#ifndef SIGRTMAX
+# define SIGRTMAX (SIGRTMIN - 1)
+#endif
+
 /* These are not interesting to print.
  * Instead of these defines it would be nice to be able to do
  * #ifdef (TYPE##_MIN) in function macro below.  */
@@ -179,6 +188,8 @@ main (int argc, char **argv)
   print_float (LDBL);
 
   /* Other useful constants */
+  printf ("SIGRTMIN=%jd\n", (intmax_t) SIGRTMIN);
+  printf ("SIGRTMAX=%jd\n", (intmax_t) SIGRTMAX);
   printf ("IO_BUFSIZE=%ju\n", (uintmax_t) IO_BUFSIZE);
 
   return EXIT_SUCCESS;