Add code to define DISABLE_CPU_FEATURES_INIT, if mingw GDB executable does not contain it

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28940 3ad0048d-3df7-0310-abae-a5850022a9f2
Add support for GDB version 7.8

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28941 3ad0048d-3df7-0310-abae-a5850022a9f2