this is a patch for Makefile's rebase target for win32gcc. It now
rebases root's dlls into an area outside the cygwin dlls' bases: cygwin
rebases from 0x70000000 downwards (as stated in /usr/bin/rebaseall), the
Makefile now uses 0x71000000 upwards.


git-svn-id: http://root.cern.ch/svn/root/trunk@10698 27541ba8-7e3a-0410-8455-c3a389f83636