When trying to use a VLAN device (e.g. "em0.123") with a dot
the library fails to parse the interface correctly. The former
pattern is much too restrictive given that almost all characters
can be coerced into a device name via ifconfig.
To prevent too much back and forth change the approach to limit
exclusion to special characters used in the library's syntax.
The list is perhaps too wide as we are only looking for interface
name boundary characters, but may also be missing others. This
decision is best left to the library authors.