Provide new gdb for Qt Creator 2.3 (7.3.x)

Gdb 7.3 has several very interesting new features, such as providing the dynamic type of an object using python scripting, and notifications of changes to breakpoints (e.g. when they are resolved by loading a shared library).

I'd like to start with this version of gdb:

  git clone git://sourceware.org/git/gdb.git
  cd gdb 
  git fetch --all 
  git checkout bc918f47c4326a431b32025f7f6418d435e90bb9 

# Result: 
# Author: Tom Tromey <tromey@redhat.com> 
# Date: Mon Jun 20 17:53:28 2011 +0000 
# * symtab.c (lookup_language_this): End loop if block is NULL. 

Try to apply all necessary patches according to share/qtcreator/patches/README.
If a patch does not fit, notify me.