[committed][gdb/testsuite] Fix gdb.python/py-breakpoint.exp with python 2

[Tom de Vries via Gdb-patches <gdb-patches@sourceware.org>]

Hi,

With a gdb build using python 2.7, I run into:
...
(gdb) python \
  gdb.events.breakpoint_modified.connect(lambda bp: print(bp.enabled))^M
  File "<string>", line 1^M
    gdb.events.breakpoint_modified.connect(lambda bp: print(bp.enabled))^M
                                                          ^^M
SyntaxError: invalid syntax^M
Error while executing Python code.^M
(gdb) FAIL: gdb.python/py-breakpoint.exp: test_bkpt_auto_disable: \
  trap breakpoint_modified event
...

This is caused by the following:
- a lambda function body needs to be an expression
- in python 2, print is a statement, while in python 3 it's a function
- a function call is an expression, and a statement is not.

Fix this by defining a function print_bp_enabled:
...
def print_bp_enabled (bp):
    print (bp.enabled)
end
...
and using that instead.

Tested on x86_64-linux.

Committed to trunk.

Thanks,
- Tom

[gdb/testsuite] Fix gdb.python/py-breakpoint.exp with python 2

---
 gdb/testsuite/gdb.python/py-breakpoint.exp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/gdb.python/py-breakpoint.exp b/gdb/testsuite/gdb.python/py-breakpoint.exp
index 857480d4b61..bd99452dd5f 100644
--- a/gdb/testsuite/gdb.python/py-breakpoint.exp
+++ b/gdb/testsuite/gdb.python/py-breakpoint.exp
@@ -816,7 +816,15 @@ proc_with_prefix test_bkpt_auto_disable { } {
     set mult_line [gdb_get_line_number "Break at multiply."]
     gdb_breakpoint ${mult_line}
     gdb_test_no_output "enable count 1 2" "one shot enable"
-    gdb_test_no_output "python gdb.events.breakpoint_modified.connect(lambda bp: print(bp.enabled))" \
+    # Python 2 doesn't support print in lambda function, so use a named
+    # function instead.
+    gdb_test_multiline "Define print_bp_enabled" \
+	"python" "" \
+	"def print_bp_enabled (bp):" "" \
+	"    print (bp.enabled)" "" \
+	"end" ""
+    gdb_test_no_output \
+	"python gdb.events.breakpoint_modified.connect(print_bp_enabled)" \
 	"trap breakpoint_modified event"
     gdb_test "continue" "False.*" "auto-disabling after enable count reached"
 }