Fix SBTarget::Launch's stop_at_entry which is ignored

[ki.stfu]

Summary

This patch fixes stop_at_entry flags in SBTarget::Launch(). Currently this flag is ignored.
I'm not sure that this arg is required but we have to fix it if it exists.

[zturner]

Not sure why this was ever a boolean in the first place instead of just having the user specify it through the launch_flags which are already passed into the function. Maybe that's why it's ignored, since the argument is redunant because you can just create the launch_flags already to have eLaunchFlagsStopAtEntry?

Either way, I guess since the argument exists, might as well use it.

[ki.stfu]

In D7271#115504, @zturner wrote:

Not sure why this was ever a boolean in the first place instead of just having the user specify it through the launch_flags which are already passed into the function. Maybe that's why it's ignored, since the argument is redunant because you can just create the launch_flags already to have eLaunchFlagsStopAtEntry?

Maybe it's true. Actually I'd like remove this argument but I afraid we can't do it. (I mean we can't change public API because we should support the backward support, right?).

Either way, I guess since the argument exists, might as well use it.

Do you mean that it's accepted? Can you commit it if it's so?

[zturner]

Yea I will commit. At some point (probably soon if you plan to continue
submitting patches) you should attempt to get commit access
http://llvm.org/docs/DeveloperPolicy.html#obtaining-commit-access

source/API/SBTarget.cpp

     {
         Mutex::Locker api_locker (target_sp->GetAPIMutex());
 
+        if (stop_at_entry)
+            launch_flags |= eLaunchFlagStopAtEntry;
+
         if (getenv("LLDB_LAUNCH_FLAG_DISABLE_ASLR"))
             launch_flags |= eLaunchFlagDisableASLR;