The variable vc-handled-backends determines which version
control systems VC should handle. The default value is (RCS CVS
SVN SCCS Bzr Git Hg Mtn Arch), so it contains all the version systems
that are currently supported. If you want VC to ignore one or more of
these systems, exclude its name from the list. To disable VC entirely,
set this variable to nil.
The order of systems in the list is significant: when you visit a file
registered in more than one system (see Local Version Control), VC
uses the system that comes first in vc-handled-backends by
default. The order is also significant when you register a file for
the first time, see
Registering,
for details.