llgs: Propagate the environment when launching the inferior from command line

Summary:
We were failing to propagate the environment when lldb-server was
started with a pre-loaded process
(e.g.: lldb-server gdbserver -- inferior --inferior_args)

This patch makes sure the environment is propagated. Instead of adding a
new GDBRemoteCommunicationServerLLGS::SetLaunchEnvironment function to
complement SetLaunchArgs and SetLaunchFlags, I replace these with a
more generic SetLaunchInfo, which can be used to set any launch-related
property.

The accompanying test also verifies that the server correctly terminates
the connection after sending the exit packet (specifically, that it does
not send the exit packet twice).

Reviewers: clayborg, eugene

Subscribers: lldb-commits, mgorny

Differential Revision: https://reviews.llvm.org/D41070

llvm-svn: 320984
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
index 7deee4b..5a74d1a 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
@@ -43,32 +43,7 @@
       MainLoop &mainloop,
       const NativeProcessProtocol::Factory &process_factory);
 
-  //------------------------------------------------------------------
-  /// Specify the program to launch and its arguments.
-  ///
-  /// @param[in] args
-  ///     The command line to launch.
-  ///
-  /// @param[in] argc
-  ///     The number of elements in the args array of cstring pointers.
-  ///
-  /// @return
-  ///     An Status object indicating the success or failure of making
-  ///     the setting.
-  //------------------------------------------------------------------
-  Status SetLaunchArguments(const char *const args[], int argc);
-
-  //------------------------------------------------------------------
-  /// Specify the launch flags for the process.
-  ///
-  /// @param[in] launch_flags
-  ///     The launch flags to use when launching this process.
-  ///
-  /// @return
-  ///     An Status object indicating the success or failure of making
-  ///     the setting.
-  //------------------------------------------------------------------
-  Status SetLaunchFlags(unsigned int launch_flags);
+  void SetLaunchInfo(const ProcessLaunchInfo &info);
 
   //------------------------------------------------------------------
   /// Launch a process with the current launch settings.