[PATCH][COMMITTED] scm-error.exp: Handle guile 2.2 backtrace output

[Doug Evans]

Hi.

Testing with recent guile had a failure in scm-error.exp.
Backtraces don't necessarily include parameter values
and can instead be printed as just "_".

2014-09-09  Doug Evans  <xdje42@gmail.com>

	* gdb.guile/scm-error.exp: Handle guile 2.2 backtrace output.

diff --git a/gdb/testsuite/gdb.guile/scm-error.exp b/gdb/testsuite/gdb.guile/scm-error.exp
index b5a1028..3de3dc2 100644
--- a/gdb/testsuite/gdb.guile/scm-error.exp
+++ b/gdb/testsuite/gdb.guile/scm-error.exp
@@ -95,7 +95,7 @@ gdb_test_no_output "set guile print-stack full" \
     "set print-stack to full, for backtrace test"
 
 gdb_test "guile (define x (top-func 42))" \
-    "Guile Backtrace:.*top-func 42.*middle-func 42.*bottom-func 42.*" \
+    "Guile Backtrace:.*top-func (42|_).*middle-func (42|_).*bottom-func (42|_).*" \
     "backtrace printed"
 
 # Verify gdb-specific errors are printed properly.