Don't change the selected platform when creating the dummy target.

[flackr]

Summary

A dummy target is used by TargetList::CreateTargetInternal to prime newly created targets. the first time this is done it creates the dummy target. The dummy target is created with the host platform (See TargetList::CreateDummyTarget) which results in switching the selected platform back to the host platform even when creating a target for a different platform. This change avoids changing the selected platform while creating the dummy target to prevent this side effect.

[clayborg]

Looks good.

lldb/trunk/source/Target/TargetList.cpp

TargetList::CreateTargetInternal (Debugger &debugger,
 
     // If we have a valid architecture, make sure the current platform is
     // compatible with that architecture
     if (!prefer_platform_arch && arch.IsValid())
     {
         if (!platform_sp->IsCompatibleArchitecture(arch, false, &platform_arch))
         {
             platform_sp = Platform::GetPlatformForArchitecture(arch, &platform_arch);
-            if (platform_sp)
+            if (!is_dummy_target && platform_sp)
                 debugger.GetPlatformList().SetSelectedPlatform(platform_sp);
         }
     }
     else if (platform_arch.IsValid())
     {
         // if "arch" isn't valid, yet "platform_arch" is, it means we have an executable file with
         // a single architecture which should be used
         ArchSpec fixed_platform_arch;
         if (!platform_sp->IsCompatibleArchitecture(platform_arch, false, &fixed_platform_arch))
         {
             platform_sp = Platform::GetPlatformForArchitecture(platform_arch, &fixed_platform_arch);
-            if (platform_sp)
+            if (!is_dummy_target && platform_sp)
                 debugger.GetPlatformList().SetSelectedPlatform(platform_sp);
         }
     }
     
     if (!platform_arch.IsValid())
         platform_arch = arch;
 
     error = TargetList::CreateTargetInternal (debugger,