[PATCH] gdb/testsuite: make gdb_get_worker_threads reads default number of threads

[Guinevere Larsen <blarsen@redhat.com>]

When a test in the testsuite attempts to collect the amount of worker
threads GDB is able to use, it calls the proc gdb_get_worker_threads,
which could understand if the number was unlimited or when it had been
explicitly defined to a number, but it was unable to understand the
default message. That lead to the following TCL error in some
situations:

ERROR: -------------------------------------------
ERROR: in testcase <path>
ERROR:  invalid bareword "UNKNOWN"
in expression "UNKNOWN / 2";
should be "$UNKNOWN" or "{UNKNOWN}" or "UNKNOWN(...)" or ...
(...)

One such example is the current buildbot instance (at least the clang
version). This commit adds a new clause to the gdb_get_worker_threads
that detects the default worker thread message.
---
 gdb/testsuite/lib/gdb.exp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index d0990dcfe0e..148476cf42d 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -10034,6 +10034,9 @@ proc gdb_get_worker_threads { {testname ""} } {
 	-wrap -re "^The number of worker threads GDB can use is unlimited \\(currently ($::decimal)\\)\\." {
 	    set worker_threads $expect_out(1,string)
 	}
+	-wrap -re "^The number of worker threads GDB can use is the default \\(currently ($::decimal)\\)\\." {
+	    set worker_threads $expect_out(1,string)
+	}
 	-wrap -re "^The number of worker threads GDB can use is ($::decimal)\\." {
 	    set worker_threads $expect_out(1,string)
 	}
-- 
2.41.0