[Qt-creator] Creator 3.1 and GDB builds without Python scripting

[André Pönitz]

Old story, next attempt: For Creator 3.1 I'd like to discontinue
support for GDB builds that do not have Python scripting enabled.

This will allow for removal of almost 2/3 of the GDB specific parts of the
debugger plugin including the compiled variety of the debugging helpers and
the use of GDB's "varobj" mechanism to create displayed data which is
clumsy to use for non-trivial displays, causes lots of frontend<->GDB
roundtrips for bigger structures and which is the main obstacle for further
cross-backend re-use of code, with the obvious consequences for both
maintenance and feature development.

Right now I believe this does not affect anyone really badly anymore.

On Linux and Windows/MinGW, we have formally required GDB version 7.2 with
Python since Qt Creator 2.5, i.e. for five minor releases when 3.1 will be
out. The only change there would be that there won't be "accidentally"
working non-Python setups anymore.

On Mac the change will affect the line of Apple's Python-less GDB builds.
Those builds have been the prefered backend for Qt Creator on Mac pretty
much until now, but are now abandoned and replaced by LLDB "upstream". Qt
Creator's LLDB support is still a bit in the fledgling stage, but reported
generally usable with 3.0, and growing. So Mac setups providing some
version of LLDB will be covered. According to Wikipedia that goes down to
Xcode 4.2/Mac OS X 10.6, theoretically, some practical evidence on such
setups would be appreciated.  

_FSF_ GDB on Mac will be unaffected, and so are the mobile platforms
(iOS is LLDB-only anyway, BlackBerry and Android have Python-enabled GDBs)

Andre'