gdb/python: Add gdb.InferiorThread.details attribute

This adds a new read-only attribute gdb.InferiorThread.details, this
attribute contains a string, the results of target_extra_thread_info
for the thread, or None, if target_extra_thread_info returns nullptr.

As the string returned by target_extra_thread_info is unstructured,
this attribute is only really useful for echoing straight through to
the user, but, if a user wants to write a command that displays the
same, or a similar 'Thread Id' to the one seen in 'info threads', then
they need access to this string.

Given that the string produced by target_extra_thread_info varies by
target, there's only minimal testing of this attribute, I check that
the attribute can be accessed, and that the return value is either
None, or a string.

1 files changed, 5 insertions, 0 deletions

diff --git a/gdb/NEWS b/gdb/NEWS
index 41ea84e..dc2cac1 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -201,6 +201,11 @@ GNU/Linux/LoongArch    loongarch*-*-linux*
      set styling').  When false, which is the default if the argument
      is not given, then no styling is applied to the returned string.
 
+  ** New read-only attribute gdb.InferiorThread.details, which is
+     either a string, containing additional, target specific thread
+     state information, or None, if there is no such additional
+     information.
+
 * New features in the GDB remote stub, GDBserver
 
   ** GDBserver is now supported on OpenRISC GNU/Linux.