acpi & AcpiGbl_DsdtIndex not set?

[scole_mail <scole_mail%gmx.com@localhost>]

I'm having an issue with ia64/ski and acpi, and would like to add the
patch below.

I'm not sure if it is a just a ia64/ski issue, but it seems like
AcpiGbl_DsdtIndex is never getting set.  From nxr, it looks like only
AcpiTbInstallFixedTable() sets it, but I'm not seeing it called.

AcpiTbInstallTableWithOverride() has a comment saying it sets it, but
I don't see AcpiGbl_DsdtIndex passed to it either.

Thanks

*** /tmp/ediff2182UZY	Sun Nov 13 14:35:05 2016
--- /home/scole/nbsd/cvs/src/sys/external/bsd/acpica/dist/tables/tbxfload.c	Sun Nov 13 14:33:42 2016
***************
*** 163,168 ****
--- 163,174 ----
  
      (void) AcpiUtAcquireMutex (ACPI_MTX_TABLES);
  
+     if (AcpiGbl_DsdtIndex == ACPI_INVALID_TABLE_INDEX)
+     {
+         Status = AE_NO_ACPI_TABLES;
+         goto UnlockAndExit;
+     }
+ 
      /*
       * Load the namespace. The DSDT is required, but any SSDT and
       * PSDT tables are optional. Verify the DSDT.