Improve recording of IA64 stack data.

Examination of the results from anole and gharial suggests that we're
only managing to track the size of one of the two stacks of IA64 machines.
Some googling gave the answer: on HPUX11, the register stack is reported
as a page type I don't see in pstat.h on my HPUX10 box.  Let's try
testing for that.

src/backend/storage/ipc/ipc.c

@@ -94,12 +94,14 @@ report_stack_size(void)
 #if defined(__hpux)
 	/* HPUX: examine process's memory map with pstat_getprocvm() */
 	int			targetpid = getpid();
-	struct pst_vm_status buf;
-	int			res;
 	int			ndx;
 
 	for (ndx = 0;; ndx++)
 	{
+		struct pst_vm_status buf;
+		const char *pagetype;
+		int			res;
+
 		res = pstat_getprocvm(&buf, sizeof(buf), targetpid, ndx);
 		if (res < 0)
 		{
@@ -108,13 +110,25 @@ report_stack_size(void)
 		}
 		if (res != 1)
 			break;
-		if (buf.pst_type != PS_STACK)
+		switch (buf.pst_type)
+		{
+			case PS_STACK:
+				pagetype = "STACK";
+				break;
+#ifdef PS_RSESTACK
+			case PS_RSESTACK:
+				pagetype = "REGSTACK";
+				break;
+#endif
+			default:
 				continue;
-		fprintf(stderr, "%d: stack addr 0x%lx, length %ld, physical pages %ld\n",
+		}
+		fprintf(stderr, "%d: stack addr 0x%lx, length %ld, physical pages %ld, type %s\n",
 				targetpid,
 				buf.pst_vaddr,
 				buf.pst_length,
-				buf.pst_phys_pages);
+				buf.pst_phys_pages,
+				pagetype);
 	}
 #else							/* non HPUX */
 	/* Otherwise: try to use pmap.  No error if that doesn't work. */