[RFA 5/5 v3] Darwin: fix SIGTRAP when debugging

[Xavier Roirand <roirand@adacore.com>]

Debugging a program under Darwin does not work:

(gdb) start
Temporary breakpoint 1 at 0x100000fb4: file /tmp/helloworld.c, line 1.
Starting program: /private/tmp/helloworld
[New Thread 0x2903 of process 60326]
During startup program terminated with signal SIGTRAP, Trace/breakpoint
trap.

Field signaled from darwin_thread_info is not initialized thus signal
sent to the debuggee is considered as not sent by GDB whereas it should.

This patch fixes this problem and also updates (change type and/or
initialize) other fields in the same structure at the same time.

gdb/ChangeLog:

        * darwin-nat.h (struct darwin_thread_info) <gdb_port,
	inf_port, msg_state>: Initialize.
        (struct darwin_thread_info) <signaled, single_step>: Change
        type and initialize.
        (struct darwin_thread_info) <event>: Initialize.

Change-Id: I0fe2a6985df9d0dfcc8a2a258a3ef70cfa19b403
---
 gdb/darwin-nat.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/gdb/darwin-nat.h b/gdb/darwin-nat.h
index 5965df08ab6..89a7c06f6a1 100644
--- a/gdb/darwin-nat.h
+++ b/gdb/darwin-nat.h
@@ -114,25 +114,25 @@ enum darwin_msg_state
 struct darwin_thread_info : public private_thread_info
 {
   /* The thread port from a GDB point of view.  */
-  thread_t gdb_port;
+  thread_t gdb_port = 0;
 
   /* The thread port from the inferior point of view.  Not to be used inside
      gdb except for get_ada_task_ptid.  */
-  thread_t inf_port;
+  thread_t inf_port = 0;
 
   /* Current message state.
      If the kernel has sent a message it expects a reply and the inferior
      can't be killed before.  */
-  enum darwin_msg_state msg_state;
+  enum darwin_msg_state msg_state = DARWIN_RUNNING;
 
   /* True if this thread is single-stepped.  */
-  unsigned char single_step;
+  bool single_step = false;
 
   /* True if a signal was manually sent to the thread.  */
-  unsigned char signaled;
+  bool signaled = false;
 
   /* The last exception received.  */
-  struct darwin_exception_msg event;
+  struct darwin_exception_msg event {};
 };
 typedef struct darwin_thread_info darwin_thread_t;
 
-- 
2.15.2 (Apple Git-101.1)