The motivation for this change is to make it simple to pass a
correctly sorted environment block to Win32 CreateProcess(). It is
also nice in other contexts that the environment variables are
sorted. The change is made for all platforms. This keeps it simple and
the only ill effect is slightly slower lookups.
Concerning the environment block passed to Win32 CreateProcess:
The environment block that is passed to CreateProcess() must be sorted
case-insensitively and without regard to locale. See
https://msdn.microsoft.com/en-us/library/windows/desktop/ms682009(v=vs.85).aspx
The need for sorting the environment block is also mentioned in the
CreateProcess() documentation, but with less details:
https://msdn.microsoft.com/en-us/library/windows/desktop/ms682425(v=vs.85).aspx
Task-number: QTBUG-61315
Change-Id: Ie1edd443301de79cf5f699d45beab01b7c0f9de3
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>