[Qt-creator] Qt Creator from git now requires up-to-date Qt 4.6

[André Pönitz]

I have two pieces of information to share:

1. Today there have been changes made to Qt Creator that require very 
   recent Qt 4.6 sources to compile.  So whoever builds Creator from sources 
   will most likely have to compile Qt first.

   The change affects only the building of Creator itself, not applications
   built with Qt Creator. It's still possible to use Qt 4.5 or even older
   for them.

2. We ran into another issue in gdb 7.0 that makes it hard, if not impossible
   for us to operate on type information for variables (see 
   http://sourceware.org/bugzilla/show_bug.cgi?id=10898). By now
   it is safe to assume that an unpatched gdb 7.0 will not be supported
   by Qt Creator, both for already released versions and the upcoming 1.3.


Andre'