[PATCH] Don't try to get the TIB address without an inferior

["Hannes Domani via gdb-patches" <gdb-patches@sourceware.org>]

The target_get_tib_address call always fails in this case, and there is an
error when changing the program with the file command:

(gdb) file allocer64.exe
Reading symbols from allocer64.exe...
You can't do that when your target is `exec'

Now it will skip this part, there is no need to rebase the executable without
an inferior anyways.

gdb/ChangeLog:

2020-03-06  Hannes Domani  <ssbssa@yahoo.de>

	* windows-tdep.c (windows_solib_create_inferior_hook):
	Check inferior_ptid.
---
 gdb/windows-tdep.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gdb/windows-tdep.c b/gdb/windows-tdep.c
index 4e5d8303ca..a3bacc2211 100644
--- a/gdb/windows-tdep.c
+++ b/gdb/windows-tdep.c
@@ -843,7 +843,8 @@ windows_solib_create_inferior_hook (int from_tty)
     }
   CORE_ADDR tlb;
   gdb_byte buf[8];
-  if (target_get_tib_address (inferior_ptid, &tlb)
+  if (inferior_ptid != null_ptid
+      && target_get_tib_address (inferior_ptid, &tlb)
       && !target_read_memory (tlb + peb_offset, buf, ptr_bytes))
     {
       CORE_ADDR peb = extract_unsigned_integer (buf, ptr_bytes, byte_order);
-- 
2.25.1