Function: set-auto-mode-1

Find the -*- spec in the buffer.
Call with point at the place to start searching from.
If one is found, set point to the beginning and return the position
of the end. Otherwise, return nil; may change point.
The variable `inhibit-local-variables-regexps' can cause a -*- spec to
be ignored; but `enable-local-variables' and `local-enable-local-variables' have no effect.